Abstract: According to the conserved nucleotide sequences of coat protein genes of Zucchini yellow mosaic virus（ZYMV），Papaya ring spot virus（PRSV）and Cucumber mosaic virus（CMV）infected chieh-qua specific primers were designed. Based on the establishment of the optimal RT-PCR for the single detection of ZYMV，PRSV and CMV，a multiplex RT-PCR protocol for the detection of three viruses on chieh-qua was developed，which provided a simple，rapid and economic method for simultaneous detection of three chieh-qua viruses to support the pathogen detection of chieh-qua technically and theoretically.

Key words: chieh-qua, Benincasa hispida（Thunb.）Cogn. var. chieh-qua How., Zucchini yellow mosaic virus, Papaya ring spot virus, Cucumber mosaic virus, multiplex RT-PCR