Concept lattice is an effective formal tool for data analysis and knowledge extraction. Constrained concept lattice, with the characteristics of higher constructing efficiency, practicability and pertinency, is a new concept lattice structure. For the automatic classification task of star spectrum, a classification rule mining method based on constrained concept lattice is presented by using the concepts of partition and extant supports. In the end, the experimental results validate the higher classification efficiency and correctness of the method by taking the star spectrum data as the formal context, so that an effective way is provided for the automatic classification of massive star spectrum.