Abstract: According to the theory of condition number of matrix, this paper provided a method for testing the reliability of predicting model,and on the basis of ridge regression theory,the method for improving unreliable predicting model was built, which was tested by predicting the residue dynamics of fenvalerate in cabbages.The results showed the precision of predicting model was increased by a big range.

Key words: Model for predicting insecticide residue, Reliability, Testing method, Improvement method