Abstract: According to the mapping relationship between the multiple secret images pixel combinations and the basis matrices, the redundant basis matrices are analyzed in the access-based multi-secret visual cryptography. A compression algorithm is proposed to decrease the size of basis matrices. The algorithm takes one column pixels as disposal unit, and satisfies the entire contrast of secret images. Based on the algorithm, new secret sharing and recovering procedures are designed for the access-based multi-secret visual cryptography. Compared with previous schemes, the present scheme can diminish the size of shares effectively, and the compression effects are obvious for the simple images.