The invention discloses a cloud cipher text access control method and a cloud cipher text access control system. The method comprises the following steps: when a user makes a request to a cloud server through an access end for accessing an encrypted file, the cloud server acquires a key cipher text corresponding to the file and judges whether the attribute of the user satisfies the access tree structure in the key cipher text; if the attribute of the user satisfies the access tree structure in the key cipher text, the cloud server makes a request to the access end for acquiring a local key in a transformation key, decrypts the key cipher text according to the local key to get an intermediate cipher text, and sends the intermediate cipher text and a file cipher text corresponding to the file to the access end; and the access end receives the intermediate cipher text, decrypts the intermediate cipher text according to a stored private key to get a plaintext key, and decrypts the file cipher text according to the plaintext key to get the file. Thus, the security of data is ensured. Moreover, the cloud server undertakes part of decryption operation, and the decryption speed and efficiency are improved.