Abstract: In this paper, a new type hybrid differential rotary table is taken as the research object, in order to improve the negative pressure of oil film, two improvement schemes are proposed. Scheme Ⅰ is at the edge of the static pressure chamber seal oil flow compensation hole, scheme Ⅱ is to increase oil hole in the dynamic pressure into the tank. The oil film pressure field and temperature field of the rotary table were numerically simulated by using the computational fluid dynamics software, and the bearing capacity, inlet flow, minimum pressure and maximum temperature rise of the oil film before and after the improvement at different rotating speeds were compared and analyzed. The results show that both schemes can effectively improve the negative pressure and the oil film characteristics are better than before the improvement. in improving the negative pressure on the applicable speed range are more wide.