We analyze stability and accuracy of fiber Bragg grating with a phaseshift mask in the preparation process. By simulation and experiments, we have verified effects of some parameters that affect stability and accuracy of preparation. Meanwhile, we show the relationship between light sensitivity and exposure in the fiber. We also study how to improve the focus effect and stability of the centre wavelength of fiber Bragg grating. As a result, we provide a new scheme for batch processing temperaturestable fiber grating wit high precision.