One of the key problems of the hydraulic design of fish pass structure is the fish first orient to the flow. Obtaining fish behavior parameter in the process of upstreaming is beneficial to the research of target fish physiological characteristics, swimming capability and its response to hydraulic environmental factors. In this paper, taking the Hypopthalmichthys molitrix as the research object, the correlation among flow velocity U, tail-beat frequency f, relative tail-beat amplitude A, absolute swimming speed V and swimming acceleration a was analysed in the state of holding station and moving forward during upstream by behavioral analysis software. Result showed tail-beat frequency and flow velocity were in a positive relationship during holding station; relative tail-beat frequency A was (0.0876 ± 0.0098) BL, while there was no clear relation between tail-beat frequency f and relative tail-beat amplitude A; during moving forward, tail-beat frequency f was greater than that during holding station, while in contrast, little difference lay in relative tail-beat amplitude A; tail-beat frequency f and absolute swimming velocity V were in definite positive relation, while there was no obvious relationship between tail-beat frequency and relative tail-beat amplitude A; in the process of H. molitrix moving forward, swimming acceleration a changed as time went by, and most of swimming acceleration varied from 0.02 g to 0.06 g[55.84%]. In the paper, experiments are conducted in the flume and we had a single flow field, but the flow field is relatively complex in natural environment. The relationship between fish behavior and hydraulic factor requires further research.