Recently, an interesting variant of chaotic image cipher using Latin square has been studied extensively, but the lack of the corresponding cryptanalysis hampers its further development. This paper performs the cryptanalysis of a newly proposed chaotic image cipher using Latin square-based confusion and diffusion. Despite the claim that the cryptosystem is of high security, we demonstrate that the cipher can be broken by chosen-plaintext attack combined with chosen-ciphertext attack. Moreover, some improvement ideas for the original algorithm are given to enhance the security.