Abstract: A method using damped least square method for spatial three-dimensional rectangular coordinate transformation is put forward,and robust estimation method for gross error detection and elimination is introduced.This method,which is not only adapted to large rotation angle,but also adapted to small rotation angle,has many characteristics,such as relying less on the initial values of 7 transformational parameters,being able to resist errors from observation values,making the calculates results more accurate,etc..The simulated example proves its validity finally.