Scallop Pationopecten yessoensis is the mainly bottom culture species in Northern coastal of China. To know it moving characteristics after seeding will helpful to improve return catch rate and to select suitable releasing site. In this paper, the pressure sensor-force gauge is used to measure the force production of scallop Pationopecten yessoensis and their escape response to predator starfish, in order to understand the movement behavioral characteristics of the scallop. According to the shell length, the scallops were divided into 3 experimental groups: big size (82.71±3.49) mm, middle size (65.76±4.20) mm and small size (32.36±2.38) mm. 15 individual of each size of scallops were measure the force production for 3 min and then to measure the force response to starfish next day. The results showed that (1) the clap rates (time/s) of big, middle and small size scallop were 0.7±1.6, 1.1±0.5 and 0.6±0.4, respectively, and the maximum contraction force (F_max, N) were 11.4±5.2, 5.9±1.3 and 1.8±0.6, respectively. The phase and tonic contractions of scallops alternated, and there were significant differences between different sizes. The larger the size, the stronger the closing force. (2) When stimulated by starfish, the F_max, clap rate, total contraction force and tonic contraction force of 3 size scallops increased significantly. Among which, the maximum contraction force (F_max, N) of big, middle and small size scallop increased to 17.1±2.8, 8.3±2.3, 2.6±0.5, respectively. However, there was no significant difference between the phase contraction force (Fphasic) with and without starfish stimulation, and there was no significant interaction between the size and the presence or absence of starfish stimulation. The force gauge method quantified the ability of the tonic contraction of scallop. In the future, it will be combined with video recording and other methods to further understand the jump or swim away speed from the predator and movement behavior characteristics of the scallop.