This paper quantitatively evaluates the simulated present-day global sea surface temperature(SST) and mixed layer depth(MLD) in BCC_CSM developed by Beijing Climate Center(BCC) in order to provide suggestions for BCC_CSM's development and improvement.The simulated SST and MLD from BCC_CSM as well as from other 15 CMIP5 models are analyzed and compared with the observed SST and MLD from World Ocean Atlas 2009(WOA09).This paper also investigates some possible reasons for the biases in these models.According to the analysis, SST in mid-high latitudes of the Northern Hemisphere in BCC_CSM have relatively large biases, while the biases are rather small in other latitudes.This paper finds that the SST biases are mainly caused by biased ocean circulation.There are large biases for simulated maximum MLD in BCC_CSM in mid-high latitudes of the Northern Hemisphere and high latitudes of the Southern Hemisphere, where many CMIP5 models have the same problem.There are also large biases for minimum MLD in mid-high latitudes of the Southern Hemisphere.In winter, the southward shift of the site where the Atlantic Meridional Overturning Circulation(AMOC) sinks leads to a cold bias of SST in high latitudes of the Northern Hemisphere.These results suggest that, in high latitudes of both the Northern and Southern Hemispheres where deep convections occur, many physical processes need to be better represented in the coupled ocean-atmosphere models including BCC_CSM, to enhance their reliability in climate prediction.