In order to understand the effect of escape opening type on the escaping behavior of Portunus trituberculatus in crab pots, the response behavior of crabs pre-stocked in pots to rigid rectangular escape vent with 40 mm height×200 mm width and meshes escape openings composed of two 40 mm×60 mm meshes in lower position and one 60 mm×60 mm mesh in higher position was observed and recorded in tank by infrared underwater camera. Both escape opening were located at the bottom edge of side panels. According to behavioral characteristics of crab behaviors, the continuous response behavior of P. trituberculatus to pots and escape openings was divided into four stages:search, detect and approach, attempt to pass, and pass through the escape openings. The video recording of the response behavior showed that, compared with those in the experimental pot with rigid rectangular escape opening, pre-stocked P. trituberculatus in pot with meshes escape opening explored more frequently and persistently. Crabs could locate, detect and approach the escape opening readily in their search behavior at the floor of pots, regardless of type of escape opening. However, the average number of times and duration of approaching the meshes escape openings were greater than those of approaching the escape rigid escape vent (P< 0.001 for average duration and P=0.061 for average number of times). For crabs approaching openings, nearly 85% of them attempted to pass through openings and no significant difference in attempt to pass through between different opening types was detected. Duration of stay in front of the escape openings of P. trituberculatus, which was considered as a significant factor influencing the attempt to pass thorough, was significantly longer (P=0.006) for meshes escape openings than that for rigid rectangular escape vent. All crabs walked sideways through escape openings, so whether crabs could pass through an rigid escape vent depended upon the relationship between carapace depth and opening height of rigid escape vent. As for the meshes escape openings, crabs preferred to pass through the lower opening and eventually succeeded in escaping. Nevertheless, the effective releasing crabs of meshes escape openings suggested that the mesh opening could be used as an effective escape device and the usage of biodegradable netting panel would be one of the technical measures to alleviate ghost fishing effect when pots were lost in crab pot fisheries.