Abstract: Cranoglanis bouderius and Onychostoma sima, the main releasing fish in Beipan River, have obvious differences in their releasing effect. We tested the two fish′s burst swimming speeds by increasing velocity method with the device made by ourself. The results show that the burst swimming speed of O.sima was higher than that of C.bouderius. The burst swimming speed and relative burst swimming speed of the two fish increased and declined along with the increasing body length with linear approximation, respectively. The investigation provides references for assessment of enhancement and releasing effect for fish from Beipan River as well as protective measures for blocking fish, luring fish and fishing boat in Beipan River in the future.