The Pacific Arctic region is experiencing rapid sea ice decline and increasing Pacific water inflow through the Bering Strait. The summer Pacific water plays distinct roles in transporting heat, freshwater and nutrients northwards to the Chukchi Sea and Canada Basin. 32690 temperature and salinity profiles from 1996 to 2021 are compiled, quality-controlled, and further used to calculate mixed layer depths and Simpson energy over the upper 60 m water column. Our results indicate that the water column over the southeast of the Bering Sea shelf is generally more well-mixed than in the northeast of the Bering Sea shelf. In spring and summer, the mixed layer depth in the southern Chukchi Sea is deeper than that in the northern Chukchi Sea but shallower than that in the northern Chukchi Sea in autumn. The influence of salinity on stratification dominates during the winter months (December to May) in the Pacific Arctic region and increases with higher latitude during summer months (June to November). Salinity-induced stratification is as important as temperature-induced stratification in the region of 60°-68° N. The mixed layer trend of the Chukchi Sea, southern Beaufort Sea and Canada Basin from 1996 to 2008 is opposite to that from 2009 to 2021. Overall, the stratification of the water column in the Pacific Arctic region has great spatial and temporal variability, and its underlying physical mechanisms need to be further studied.