Abstract: Abstract: Watermelon peelis a typical biomass waste, which is stacking with a speed of 70 million tons per year in China. While at the same time, watermelon peel is mainly disposed by landfilling or incinerating with other waste, leading to secondary pollution and a squandering of resources. Therefore, using advanced green technology, biomass wastes represented by watermelon peel can be effectively transformed into environmentally friendly alternative resources. In this study, watermelon peel was selected as typical biomass waste to explore the resource potential of microwave hydrothermal (MHT) treatment under drying, acid and alkali treating process. This work simultaneously considered the solid phase products and liquid phase products after MHT treatment. Results showed that when the MHT temperatures were between 130 ℃ and 190 ℃, the yield of hydrochar could reach 86.01% after alkali treatment (170 ℃), significantly higher than that in drying treatment and acid treatment. However, its calorific value was lower than 17 MJ/kg, which means it had no potential to be a fuel. Meanwhile, drying and acid treatment could not only obtain hydrochar conforming to standard coal whose high heating value is in range of 17-28 MJ/kg, but more importantly, high value-added 5-hydroxymethylfurfural (HMF) and furfural (FF) could be obtained in liquid phase products. The yields of HMF and FF in these treatments were significantly affected by MHT temperature. The results of Fourier Transform infrared spectroscopy indicated that the watermelon peel was hydrolyzed and decarboxylated under MHT conditions after drying and acid treatment, and became more intense with increasing temperature. The decrease of pH and the leaching efficiency of total organic carbon with the increase of MHT temperature can also reflect the intensification of hydrolysis reaction and decarboxylation reaction. In addition, the SEM image showed that a large number and size of microspheres appeared on the surface of the hydrochar obtained by the drying treatment and the acid treatment, which may affect the performance of the hydrochar and the yield of HMF. Moreover, the acid treatment can obtain a higher HMF yield of 3.3 % under MHT temperature of 130 ℃ at a low energy consumption as compared with the drying treatment. This means that 33 kg of HMF can be obtained by treating one ton of dried watermelon peel under this condition. According to the market price of HMF, the value is 165 182 yuan which means that the economic value of processing a ton of fresh watermelon peel is 6 607 yuan. In addition, the hydrochar yield of 25.96% obtained by acid treatment under corresponding MHT temperature also showed its economic value due to the market price of standard coal (700 yuan per ton). In addition, the simple economic calculation shows that the energy consumption of the process for treating 1 ton of fresh watermelon peel is only 66 yuan. The superiority of acid treatment on the transformation of watermelon peel resources was explained. Therefore, from the perspective of comprehensive economic output and input, the process has great potential for industrial application.