The switching performance of high-speed optical-switching-integrated chips is to a great extent dependent on the carrier injection technique, which is accompanied by the thermo-optic effect. In this paper, we put forward a synchronous driving scheme for the silicon-based Mach-Zehnder interferometer (MZI) optical switches, which is capable of critically compensating for the temperature variation with carrier injection to the p-i-n diode on one arm of the MZI by applying a synchronous modulating voltage to the silicon resistive heater on the other MZI arm. The synchronous compensation mechanism is identified by experiments and simulation. Our experimental data show that, by comparison with the traditional driving scheme, the synchronous driving scheme can improve the extinction ratio by 1 dB, along with a better switching waveform.