As the final step in the fabrication of a force sensor， the sensor is calibrated to obtain its true performance parameters. Therefore， the accuracy of a force sensor is determined by its calibration accuracy. Generally， calibration is an ideal process， but angle deviations can reduce the calibration accuracy. To achieve high-precision calibration of piezoelectric three-dimensional force sensors， a calibration angle-deviation factor is introduced into the original calibration model. For factors such as uneven surface， sensor angle， and deflection of force source， calibration model improvement， parameter acquisition， and decoupling effect analyses are performed. First， the angle-deviation factors in sensor calibration are analyzed. A dial indicator and an inclinometer are used for measurement. Second， considering the unknown parameters， an appropriate objective function and constraint conditions are established. Based on the optimization algorithm， model parameters are solved and sensor calibration to remove calibration angle deviation is realized. Finally， two models are used to decouple the experimental data. The effectiveness of the new model is proven from the perspective of the mean and extreme values of the decoupling error. Results show that compared to the old model， the mean value of decoupling error in most directions decreases by approximately 80%， and the extreme value decreases by 20%-49%， thereby verifying the effectiveness of the proposed method. On this basis， the influence of angle deviation on sensor coupling characteristics is analyzed， and the coupling ratio introduced by each link deviation is obtained. As the calibration angle-deviation factor accounts for over 70% of partial coupling coefficients， the influence of angle deviation cannot be ignored and should be controlled.