Abstract: Based on the real-time data of sinking depth and distance of net mouth of falling-net by SDKN-500 net monitor in November 2014, we analyzed the sinking and closing performance of falling-net. The results show that: 1) The sinking and closing speeds would not mutate when pursing the purse line with retardation time of 120.7s;2) The net mouth was not completely closed when it reached the maximum depth (averagely 82.0 m), and did not rise up until it was completely closed (averagely 68.0 s) and stayed for a while (averagely 9.8 s); 3) The different operating conditions could be divided into the shooting time (0 s), the pursing time (averagely 104.0 s), the time when the closing speed mutated (averagely 224.7 s), the time when the net mouth reached the maximum depth (averagely 266.6 s) and the time when the net mouth was completely closed (average 334.6 s) in sequence, which were the five key time nodes determining the fishing performance of falling-net; 4) The sinking speeds of the four periods were 0.419 m · s^-1, 0.238 m · s^-1, 0.233 m · s^-1 and -0.021 m · s^-1, respectively, showing a decreasing trend with fluctuation in the middle of settlement; 5) The closing speeds of the four periods were 0.103 m · s^-1, 0.105 m · s^-1, 0.253 m · s^-1 and 0.424 m · s^-1, respectively, showing an increasing trend. The closing speed of net mouth increased firstly and then decreased at the beginning of settlement, and the closing speed showed a significant increasing trend in the later period of settlement. It is suggested to increase the hauling speed to avoid fish escape.