Concerning the problems of Attribute-Based Encryption (ABE) such as high computational consumption and lack of flexibility in mobile Internet, a dynamic trust level based Ciphertext-Policy ABE (CP-ABE) scheme was proposed. Firstly, the "trust level" attribute was defined to indicate user's trusted level and divide users into different classes. User with high "trust level" was be able to decrypt the message in a constant computational overhead. Meanwhile, Central Authority (CA) was allowed to evaluate user's access behavior within the certain time threshold. Only the user's "trust level" was updated dynamically by the updating algorithm instead of complete re-generating of secret key. Theoretical analysis and experimental results show that, with the growing proportion of high "trust level" user, the total time consumption of the proposed scheme was decreased until being stable and finally was superior to the traditional scheme. The proposed scheme can improve the access control efficiency in mobile Internet on the premise of keeping the security standard.