Abstract: ‘Bai Yi Tang Di’ muskmelon were used as test materials, a two-factor random block design was used.Different consistences of chitosan oligosaccharide solutions including(25,50,75,100,125 mg·L^-1) were used for soaking seed, foliar spray and root irrigation treatments, the effects of different application methods of chitosan oligosaccharide on melon seedlings were studied, in order to provide reference for the application of chitosan oligosaccharide in vegetable seedling raising.The results showed that the seeds which were soaked in 75 mg·L^-1 chitosan could significantly increase the germination rate of muskmelon seeds.According to the experiments, 75 mg·L^-1 soaking seed, 50 mg·L^-1 foliar spray, and 100 mg·L^-1 root irrigation were the best consistence for enhancing the quality of muskmelon seedlings among all the means.In each application method, the quality of muskmelon seedlings which were dealt with foliar spray was the best, followed by the root irrigation treatment, and the soaking seed treatment was the weakest, but they were all significantly better than comparing.