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.