diff --git a/tools/script/tquic_time_cwnd.py b/tools/script/tquic_time_cwnd.py
new file mode 100755
index 00000000..9a0bbd8a
--- /dev/null
+++ b/tools/script/tquic_time_cwnd.py
@@ -0,0 +1,90 @@
+#!/usr/bin/env python3
+
+# This tool is used to analyze TQUIC debug logs and produce a time-cwnd figure
+# for the specified QUIC connection.
+
+import re
+
+from datetime import datetime
+import argparse
+import matplotlib.pyplot as plt
+
+
+def parse_log(log_file, id):
+    with open(log_file, "r") as file:
+        log_data = file.readlines()
+
+    timestamps = []
+    inflights = []
+    cwnds = []
+
+    # Refine the regular expression to match timestamps and cwnds
+    timestamp_pattern = re.compile(r"\[(\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d{3})Z")
+    cwnd_format = r"{} [a-zA-Z]* BEGIN_ACK inflight=(\d+) cwnd=(\d+)"
+    cwnd_pattern = re.compile(cwnd_format.format(id))
+
+    for line in log_data:
+        timestamp_match = timestamp_pattern.search(line)
+        if not timestamp_match:
+            continue
+
+        cwnd_match = cwnd_pattern.search(line)
+        if not cwnd_match:
+            continue
+
+        timestamp_str = timestamp_match.group(1)
+        timestamp = datetime.strptime(timestamp_str, "%Y-%m-%dT%H:%M:%S.%f")
+        inflight = int(cwnd_match.group(1))
+        cwnd = int(cwnd_match.group(2))
+        timestamps.append(timestamp)
+        inflights.append(inflight)
+        cwnds.append(cwnd)
+
+    return timestamps, inflights, cwnds
+
+
+def plot_offsets(timestamps, inflights, cwnds, connection_path_id):
+    # Set output file name
+    ids = connection_path_id.split("-")
+    cid = ids[1]
+    pid = ids[2]
+    output_file_name = "tquic_time_cwnd_{}_{}.png".format(cid, pid)
+
+    plt.figure(figsize=(20, 6))
+    plt.plot(timestamps, inflights, label="inflight", linestyle="-", linewidth=0.5)
+    plt.plot(timestamps, cwnds, label="cwnd", linestyle="-", linewidth=0.5)
+    plt.xlabel("Time")
+    plt.ylabel("Cwnd/Inflight")
+    plt.title(f"Congestion window by Time in Connection {cid} Path {pid}")
+    plt.legend()
+    plt.gca().xaxis.set_major_formatter(
+        plt.matplotlib.dates.DateFormatter("%H:%M:%S.%f")
+    )
+    plt.savefig(output_file_name)
+    print("Found %d items, figure %s" % (len(timestamps), output_file_name))
+
+
+if __name__ == "__main__":
+    # Set up the command line argument parser
+    parser = argparse.ArgumentParser(
+        description="Analyze TQUIC logs to get the relationship between cwnd/inflight and time."
+    )
+    parser.add_argument(
+        "-l",
+        "--log_file",
+        type=str,
+        help="path to the TQUIC debug log file",
+        required=True,
+    )
+    parser.add_argument(
+        "-c",
+        "--connection_path_id",
+        type=str,
+        help="connection path id, eg. SERVER-c6d45bc005585f42-0",
+        required=True,
+    )
+    args = parser.parse_args()
+
+    # Calling with command-line arguments
+    timestamps, inflights, cwnds = parse_log(args.log_file, args.connection_path_id)
+    plot_offsets(timestamps, inflights, cwnds, args.connection_path_id)
diff --git a/tools/script/tquic_time_offset.py b/tools/script/tquic_time_offset.py
index c0bd8f0d..5aa122e3 100755
--- a/tools/script/tquic_time_offset.py
+++ b/tools/script/tquic_time_offset.py
@@ -9,8 +9,11 @@
 import argparse
 import matplotlib.pyplot as plt
 
-STREAM_SEND_FORMAT=r"{} sent packet OneRTT.*?STREAM id={} off=(\d+) len=\d+ fin=(?:true|false)"
-STREAM_RECV_FORMAT=r"{} recv frame STREAM id={} off=(\d+) len=\d+ fin=(?:true|false)"
+STREAM_SEND_FORMAT = (
+    r"{} sent packet OneRTT.*?STREAM id={} off=(\d+) len=\d+ fin=(?:true|false)"
+)
+STREAM_RECV_FORMAT = r"{} recv frame STREAM id={} off=(\d+) len=\d+ fin=(?:true|false)"
+
 
 def parse_log(log_file, cid, stream_id, recv):
     with open(log_file, "r") as file:
@@ -68,21 +71,29 @@ def plot_offsets(timestamps, offsets, connection_trace_id, stream_id):
         "-l",
         "--log_file",
         type=str,
-        help="Path to the TQUIC debug log file",
+        help="path to the TQUIC debug log file",
         required=True,
     )
     parser.add_argument(
         "-c",
         "--connection_trace_id",
         type=str,
-        help="Connection trace id, eg. SERVER-c6d45bc005585f42",
+        help="connection trace id, eg. SERVER-c6d45bc005585f42",
         required=True,
     )
     parser.add_argument(
-        "-s", "--stream_id", type=int, help="Stream id, eg. 0", required=True
+        "-s",
+        "--stream_id",
+        type=int,
+        help="stream id (default 0), eg. 0",
+        default=0,
     )
     parser.add_argument(
-        "-r", "--recv", type=bool, help="Recv side instead of send side", default=False
+        "-r",
+        "--recv",
+        type=bool,
+        help="recv side instead of send side (default false)",
+        default=False,
     )
     args = parser.parse_args()