Abstract:This paper deals with the use of spatial autocorrelation method to estimate the insect population density on a comparatively large area through a survey on several small sample plots, basing on the spatial correlation of insect population. The estimated formula of autocorrelation variance is : r*=∑(z(xi+h)-z(xi))2/2N. The linear estimated coefficient equation is : A(?)=M. The residuals of estimation have been worked out while the calculation of the population density of Dendrolimus punctatus is conducted as example. This method may be used to estimate the population density of agricultural and forest insects, the level of damage, etc.