Abstract: After the attitude being stabilized, restraining the range dispersion of long-range rocket becomes the more important problem. The effect of range correction system of long-range rocket adopting SINS is analyzed through numerical simulation. The range correction efficiency can be enhanced obviously with strap-down SINS adopted, and the precision of the method for the quadratic model is higher than that for the linear model. After the instrument error of SINS is analyzed, it can be concluded that the quadratic model is more sensible to navigation error, and with instrument error taken into account, the linear model is better than the quadratic model. The range correction method error decreases with the navigation time but the instrument error increases, so the best navigation time should be chosen with both sides considered.