To improve the performance of user revocation and ciphertext update, a searchable attribute-based encryption scheme for dynamic user groups is proposed. A binary tree is applied to manage the revocation list. The user revocation will be achieved by adding revoked users to the revocation list and informing the cloud server to update the ciphertexts. To relieve the limitation of the number of system users, the nodes of the user binary tree will be re-used by new users if the random values in the nodes could be updated when user revocation occurs. Besides, a ciphertext search function, based on bilinear pairing, is provided and all revoked users are not allowed to perform the search algorithm. The security analysis proves that the proposed scheme is IND-CPA secure under the random oracle model. The performance analysis shows that the proposed scheme outperforms other existing solutions in terms of computational overhead.