The invention belongs to the technical field of biological detection, and particularly relates to an SSR primer and method for detecting the purity of cucumber hybrid F1 'Baoke No.1' seeds. The method comprises the steps that 1, cucumber genomic DNA is extracted; 2, an SSR specific primer is selected for PCR amplification; 3, polyacrylamide gel electrophoresis is carried out on a PCR amplification product, and an SSR standard diagram of a 'Baoke No.1' variety is manufactured; 4, the relative position of a gel strip is compared with the standard diagram of the 'Baoke No.1' variety, and the purity of the seeds is detected. According to the method, the hybrid 'Baoke No.1' seeds can be separated from male parent and female parent seeds of the hybrid 'Baoke No.1' seeds within one day, the purity of the seeds can be detected fast and accurately, and the advantages of being convenient to operate, good in repeatability, accurate in result and the like are achieved. The method can replace a traditional hybrid seed purity detecting method, is popularized and applied to the seed producing, reproducing and distributing business of 'Baoke No.1', and has high commercial value.