Abstract: In currently range data processing,the estimate of parameters and patch calculating usually use polynomial to approximate,which often make much more truncation errors.A method to approximate the trajectory by using the fine nature of spline functions as the base is proposed.Through integrating the spline function and recursive,a recursive calculation of spline function leastsquare approximating approach is given.The simulation demonstrates the method can save memory of computer and improve the accuracy and speed greatly.It is a practice method in project.