Abstract: Mutuo of Tibet is located at the belt sewing Europe-Asia block and Indian Ocean block. The conditions of landform, relief, geology and weather in the area are very complicated. As Mutuo is the blank area of base information in China, it is difficult to survey it by traditional methods. The refining local 1'×1' quasi-geoid has been built by using the earth's gravity field model, the local gravity anomalies and relief rectification. The results show that the relative accuracy of this engineering quasi-geoid has reached 0.025m. It can substitute direct leveling and satisfy the need of the local engineering construction.