Abstract: Watermelon mosaic virus (WMV) and Cucumber mosaic virus (CMV) were detected from one mix-infected pumpkin（Cucurbita moschata）plants in Liaocheng, Shandong Province. The nucleotide sequences of coat protein (CP) gene and the 3′-untranslated regions (3'-UTR) of WMV (WMV-liaocheng) and CP gene of CMV (CMV-liaocheng) were determined from RT-PCR derived cDNA clones. Compared with sequences of corresponding viruses that are available in the GenBank, the cp genes of WMV-liaocheng and CMV-liaocheng shared similarity of 91.2-98.0%, 77.0-97.9% at nucleotide level, and identity of 96.4-98.5%, 81.2-99.1% at amino acid level, respectively. The phylogenetic trees constructed with the complete nucleotide sequence of the CP genes showed that 18 WMV isolates were clustered into 3 groups and WMV-liaocheng belonged to group Ⅲ; 30 CMV isolates were divided into 2 subgroups, and CMV-liaocheng, Fny, Ixora, O, Y and NT9 were in subgroup I (CMV-I). There were probably recombination event during the evolution of CMV-liaocheng.