Abstract: This paper combines differential interference contrast microscopy with the polarization phase-shifting interferometric technique.This method can be employed to accurately determine the temperature variance of the micro fluid.Based on the introduction of the principle of differential interference contrast microscopy,the systemic errors are investigated,which indicates that the linear error of the rotary phase shifter is the primary error.Each degree deviation by the phase shifter will introduce 2×10^-5 deviation in the refractive index and 0.3℃ deviation in the temperature.Based on the relation between the refractive index and the phase difference,the temperature distribution variance in micro-fluid is calculated.The experimental data are consistent with the theoretical calculation.