Based on the modulation transfer spectroscopy technique, the frequency locking of the distributed feed back laser on the ⁸⁷RbD2 line F=2→F?=3 is realized, and the multi-parameter pairs such as modulation frequency, demodulation phase and pump light polarization are theoretically and experimentally studied. Modulating the effects of the shifted spectral signal provides a basis for selecting and optimizing the modulation transfer spectral stabilization technique. The results show that the best frequency locking signal can be obtained when the pump modulation frequency is between 9~15 MHz and the phase change of the modulation signal is near π/5. In the experiment, when the modulation frequency is 12.5 MHz, the polarization angle of pump and probe light is 90^o, and the applied magnetic field is 5 Gs, the amplitude and zero slope of modulation transfer spectroscopy signal are optimized by optimizing the demodulation signal phase and proportion, integral,differential control parameters, and the high-precision frequency locking of DFB laser is realized.The frequency line after the frequency-locked laser is about 1.6 MHz, and the frequency stability is less than 1.75×10^-9, it can be used as a light source in the cold atom interference experiment.