FY3A/VIRR SST (Sea Surface Temperature) is cooler than other reference SST, mainly because the radiation emitted from ocean has to go through a longer atmospheric path before reaching the VIRR instrument at higher zenith angles. Only when the satellite zenith angles less than 50°, is SST evaluated. The disadvantage of limiting zenith angle leads to the loss in geographic coverage. The brightness temperatures for channels 108 μm and 12 μm are examined for all pixels within a 3×3 pixel box centered on the pixel being spatial uniformity tested, and the cloud contaminated pixels are identified. The climate threshold test is also introduced to further eliminate the outliers. After the improvement of FY3A/VIRR SST algorithm, the global coverage of daily SST is decreased, but the consistency of SST is increased, and cloud contamination phenomena are suppressed, especially for monthly SST. Comparison with the global grid daily OISST within 70°N to 70°S of latitude, the global accuracy of FY3A/VIRR SST is -023 ℃±174 ℃. The negative bias shows that the effect of clouds and aerosols still exists. RMS of the improved FY3A/VIRR SST is 174 ℃, which quite agrees with the calibration accuracy (16 K) of the FY3A VIRR 11 μm channel.