Abstract: Jinfu K8’watermelon was used as the experimental materials,and CK（commercial watersoluble fertilizer）,BS（biogas slurry）,BSF（biogas slurry mixed fertilizer）treatments were set,the effects of different treatments on growth,photosynthesis,fruit quality,and heavy metal content of watermelon plants were studied by sand-cultivation method,in order to provide reference for the utilization of biogas slurry.The results showed that the growth rate of watermelon plants under BSF treatment was not significantly different from that under CK treatment,but significantly higher than that under BS.The Pn of CK,BS and BSF were significantly different among the treatments.There was no significant difference in Cond between BSF and CK,but it was significantly higher than BS.The weight per fruit of BSF was higher than CK by 48.6%,BS lower than CK by 17.6%.The soluble solid content of BS and BSF increased by 26.2%and 38.1%,the soluble sugar content by 19.4%and18.3%,the soluble protein content by 14.6%and 72.9%,and the vitamin C content by 16.6%and42.9%compared with CK.Pb content in root of BS and BSF significantly increased,but decreased the Pb content in shoot compared with CK.Cr content of root under BS treatments was increased,Cu content of root under BSF treatments was decreased,compared with CK in the same tissue of watermelon.The heavy metal contents of fruits were different among different treatments,while they were all below the standard limit.Based on the above results,BSF not only ensures plant growth rate,but also has a positive effect on improving photosynthesis and fruit quality of watermelon,and does not cause the risk of heavy metal accumulation in watermelon fruits.