Abstract: Studies the hydraulic automatic transmisson and shift process with model based data acquisition system. Using dSPACE, a model based data acquisition system has been developed, that can collect control signals and state parameters of hydraulic automatic transmission realtime in the shifting process. The evaluation of the relationship among parameters during the shift process can be much more direct. Test results showed that the shift torque is affected by the initial offgoing duty while the offgoing duty slop in the torque phase, while the stage of inertia phase is influenced by the initial oncoming duty.