In order to realize the π phase-shift fiber grating fabrication with different coupling coefficients by shielded method, the phase-shift principle is analyzed, and the method of controlling the coupling coefficient of π phase-shifted fiber grating by regulating the length of shielded length and the number of occurrences of π phase shift is proposed. The transmission matrix method is used to simulate the transmission spectrum change during the phase-shifted grating fabrication process. The influence of shielded length on the transmission spectrum of the phase-shifted fiber grating is analyzed under different grating fringe visibility. The phase-shifted fiber grating fabrication experiments are carried out based on different shielded length. The results show that the effective control of the phase-shift fiber grating coupling coefficient can be achieved by adjusting the shielded length and the number of phase shift cycles.