The phenomenon of heteroscedasticity in classic linear regression model was investigated and a hot issue about the estimation of heteroscedastic was discussed.With the help of orthogonal array
a nonparametric estimation method with simple calculation was proposed
which did not rely on the distribution of data. This method was applied to a specific case with data of three dimensions
which was studied the influence of three industries on the GDP and was compared with the result in the existed literature.Comparison of the results indicate that the estimation of heteroscedastic by orthogonal array is a relatively efficient way.