Abstract: In watermelon growing period(vine-extending stage, flowering and fruit setting stage, fruit expanding stage), spray on the leaf blade with bio-type organic nutrition agent Yu Hua Ling , promote plant growth stronger , make leaves dark green with thick shape ,enhance the ability of leaves, photosynthesis .In the vine-extending stage and fruit expanding stage, spray on the leaf blade with yuhualing no.1, can promote bind growth and supplementary nutrient and postpone agine. In flowering and fruit setting stage, spray on the leaf blade with yuhualing no.3, can regulating vegetative and reproductive growth, increase output of fruit .The result show that, can bring a growth of 25.4% for fruit-beaing number per plant, and 12.22% for per fruit weight and 40.72% for yield. And preliminarily studied at the nutrition content of leaf and resistance.