For the ciphertext storage and query in the DAS (database as service) model, this paper presents a ciphertext-query algorithm based on the filtering query in database. In the data storage process, the algorithm uses a given metadata set to encode the plaintext which needs protecting, generates and stores the corresponding ciphertext index code. In the data query process, the algorithm transforms the original query statement into ciphertext based on the index code to help database server complete the ciphertext-only query task. In this paper, we implement the algorithm using Oracle system and figure out the filtration rate, the detection rate and the execution time of the algorithm. The experimental statistics show that our algorithm has good performance.