In order to apply the deterministic contract decomposition algorithm to decompose contract energy， the typical load curve must be prepared. The abnormal historical load data can affect the validity of typical load curve. By referring to the contour map method of computational statistics， constructing the hierarchy tree based on hierarchical clustering method and mapping samples to the leaf nodes， a new load shape outlier identification method is proposed. The new method is combined with t test to identify and correct the load outlier. The historical data of power grid in Zhejiang Province is used to test the suggested approach and the result indicates that the algorithm is simple and effective.