To calibration the signal-to-noise ratio（SNR）of split-focus plane polarization image sensors， a calibration experiment of the SNR of each channel of a split-focus plane polarization image sensor was designed. The SNR parameters of the split-focus plane polarization image sensor were studied in terms of their influence on the polarization angle measurement results， the SNR calibration principle， and the calibration experiment procedure. The calibration principle of SNR was obtained based on the structure of the split-focus plane polarization sensor and the mathematical model of the digital image sensor. Then， the polarization angle measurement results were simulated under different SNR and different incident angle line polarization light cases. Subsequently， the device structure and experimental procedure of the calibration experiment were designed according to the calibration principle. Finally， an actual calibration was performed and the experimental data were analyzed. The simulation results show that the larger the SNR of the focal plane polarization image sensor， the higher the accuracy of polarization angle measurement， and the angle of incident polarized light also affects the measurement accuracy. The actual test results of the SNR of each channel of the focal plane polarization image sensor show that the difference between the calibration value and the index value is no more than 0.55 dB.The experimental results prove that the method is accurate and effective， and can better accomplish the calibration task of SNR for each channel of the split-focus plane polarization image sensor.