Using ANSYS, a two-way fluid-structure interaction model of a lock plane valve was established; unsteady lifting was simulated with a dynamic mesh and user-defined functions. Modal, displacement, and flow features were analyzed. Results show that wet modal frequencies are much lower than dry ones; The dominant frequencies of the vertical response are mainly distributed within 0~10 Hz and do not correspond directly to the low-order wet modal frequencies. Lifting speed alters pressure distribution. At medium speed, transient negative pressure appears beneath the valve bottom edge at small openings, and a sustained negative pressure zone forms at the culvert top at medium-to-large openings. Negative pressure increases transverse and longitudinal pressure gradients, intensifying lateral and vertical displacements. Medium-speed lifting maintains strong negative pressure in the slot region, showing higher cavitation sensitivity. Rapid lifting shortens negative pressure development, reducing structural response and cavitation sensitivity. The results provide a reference for valve design and operation.