Abstract: As an effective method for solving the morbidity normal equation,Ridge estimation has been widely studied and applied in processing of the measurement data,but the method changes the equivalent relationship and the result is a biased estimate.The iteration by correcting characteristic value does not change the equivalent relationship,but there are few studies on the limitations and the application scope of the method.With comparing the Ridge estimation method and the Iteration by correcting characteristic value,and analysing the characteristics of two methods to guide the application,an improved iteration by correcting characteristic value using the ridge parameters was proposed in this paper.This method not only reduces the iterative times and advances efficiency,but also has the same precision with the originality method.