In order to discuss the influence of the crosstalk effect on a Grating Light Modulator(GLM) driven by a passive matrix, an electrical model of the GLM array addressed by the passive matrix is established. The operation principle and the driving voltage of the GLM are presented, and the electrical model is analyzed and simplified according to the Kirchhoff's Current Law(KCL) and Kirchhoff's Voltage Law(KVL).The voltage relationships among the half-selected pixel, non-selected pixel and the all-selected pixel are obtained.Then, the operating voltage and the pull-in voltage of the GLM are measured by an experiment and the crosstalk effect is validated by another experiment, so that the relationship between the ±1 order diffractive intensity of those three kinds of pixels and the driving voltages of all-selected pixels is gained.Finally, two methods for restraining the crosstalk effect are proposed.The experiment shows that the operating voltage and the pull-in voltage of the GLM are 8.0 V and 8.5 V respectively.It also indicates that the voltage of half-selected pixel is approximately half of the all-selected pixel, and is much larger than that of the non-selected pixel, which is consistent with the theory of crosstalk effect.These results illustrate that the crosstalk effect can reduce the contrast ratio and light utilization of the GLM, but selecting a lower driving voltage can realize the monolithic integration of the GLM and the active matrix and can eliminate the crosstalk effect.