Abstract: On the basis of the theory of least-squares collocation (LSC), the approach used to define a local covariance function is described.This paper selects a 6°×6°test area (30°N~36°N, 96°E~102° E)in western China, and carries out an experiment for local geoid determination by using LSC and combing terrestrial gravity data, 30"×30" digital terrain model and EGM96 geopotential model.The 2.5'×2.5' gridded geoid heights are obtained.