— This paper proposes a new algorithm to identify and compose building blocks based on minimum mutual information criterion. Building blocks are interpreted as common subsequences between good individuals. The proposed algorithm can extract building blocks in population explicitly. The additively decomposable problems and hierarchical decomposable problems are used to validate the algorithm. The results are compared with Bayesian Optimization Algorithm, Hierarchical Bayesian Optimization Algorithm, and Chi-square Matrix. This proposed algorithm is simple, easy to tune and fast.