The invention relates to a cyclic RNA molecular marker for diagnosis of gastric cancer, the cyclic RNA molecular marker is characterized in that the cyclic RNA is hsa-circ-0001017, the invention also provides a method for detection of the cyclic RNA molecular marker in plasma, and the method comprises the following steps: (1) collecting blood, and extracting total RNA in the plasma; (2) performing reverse transcription of the total RNA into cDNA; (3) performing droplet digital PCR detection of a cDNA solution of the step (2) by use of specific amplification back-to-back primers and amplification upstream and downstream primers of housekeeping gene GAPDH, after the completion of the reaction, detecting fluorescence signal values of all droplets, setting a threshold, and determining whether the droplets include the cyclic RNA or the housekeeping gene GAPDH, wherein the droplets higher than the threshold are positive droplets, and the droplets below the threshold are negative droplets; and (4) counting the number of the positive droplets, and calculating the copy number of the hsa-circ-0001017 and the housekeeping gene GAPDH in the plasma for quantitative detection of the hsa-circ-0001017 and the housekeeping gene GAPDH in the plasma. Compared with the prior art, the advantages are that the hsa-circ-0001017 can be specifically expressed in plasma in patients with gastric cancer, and can be used as a new molecular marker for diagnosis of the gastric cancer.