To effectively compensate the hysteresis nonlinearity of piezoelectric ceramics, a modified PI model based on STOP operator was proposed to avoid the complex processing in solving inverse model and time consuming in interpolating method of the traditional PI model based on PLAY operator. Firstly, traditional PI models based on PLAY operator or STOP operator were introduced. Then, modified PI model based on STOP operator was established by taking an expecting displacement as the input and a control voltage as the output, and the model was used as a feedback controller to compensate the hysteresis effect of piezoelectric ceramics. To balance the ability of local optimization and global optimization, the particle swarm optimization algorithm was improved to identify the weights of operators with different thresholds. Finally, the modified PI model was used to verify experimentally the compensating effects for the hysteresis nonlinearity. Two groups of experiments were carried out, and the results show that the hysteresis has been compensated well by modified PI model with the error no more than 1% no matter the input is continuous or random. It concludes that, the modified PI model based on STOP operator is of great value in the field of piezoelectric ceramic control.