Crosstalk from square wave modulation signal causes output signal instability and deteriorates threshold value and scale linearity in FOG. Excessive modulation uses bigger phase to restrain noise. According to the principle of correlative demodulation and crosstalk model, the output expression of FOG containing excessive modulation crosstalk would be derived and the modulation phase is an important effect factor of crosstalk. To solve the problem that deeper modulation phase would enlarge the crosstalk, a method of variable square wave modulation was put forward to restrain the crosstalk. With periodicity of response cosine function and repeatable modulation wave, the modulation signal and demodulation signal would be generated nearly independently. The correlative demodulation result would be zero in some delay time and reduce the crosstalk amount. Simulation and experimental results indicate that this method can improve one order of magnitude of restrain effect of crosstalk compared to square wave modulation. The zero bias stability and threshold value would be improved about 40% compared with square wave excessive modulation.