In order to improve the security and efficiency of data access control under multi-authority environment, an access-tree based multi-authority ABE (ATB-MAABE) has been proposed in this paper. In ATB-MAABE, CA is only used for public parameters generating and authority verification, which reduces the security risk introduced by CA. Access control policy is defined by the DO(data owner)， and the attribute-based secret key components are generated by DO and different attributes authorities. By using the access tree based control policy, this scheme can prevent the attacks from the user and authority collusion. Furthermore, the user's global identifier (GID) is not required in secret key generating, which can support anonymous data control and sharing. Finally, the security proof is given by using the Decisional Bilinear Diffie-Hellman (DBDH) assumption, and the experiment results show the efficiency of this scheme in encryption/decryption operations.