In order to reduce the use of nonrenewable resources of peat and the production cost of soilless culture substrates, with the melon variety “Yangjiaomi” as the test material, we mixed the rice husk ash and the commercial finished cultivation substrate according to different volumes［1∶5(T₁), 2∶4(T₂), 3∶3(T₃), 4∶2(T₄) and 5∶1(T₅)］, and with the commercial finished cultivation substrate without added husked ash as CK, to study the physical and chemical properties of different substrates and their effects on melon growth, leaf chlorophyll content, photosynthetic gas exchange parameters and fruit quality. The result shows: (1) adding a certain amount of rice husk ash to the commercial finished cultivation substrate can significantly improve the aeration of the substrate, increase the pH and EC (electrical conductivity) of the mixed substrate and observably inhibited the number of microorganisms in the substrate. (2) Compared with CK, the right amount of rice husk ash mixed matrix can significantly promote the growth of melon plants. Among them, under T₂ treatment, the plant height of the melon plant, root vitality and root shoot ratio significantly increased by 14.69%, 19.73%, and 23.08%, respectively. (3) Under T₂ treatment, the chlorophyll content, net photosynthetic rate, stomatal conductance and transpiration rate of melon leaves increased significantly. (4) The transverse diameter, longitudinal diameter, single fruit weight and yield per plant significantly increased compared with the control, the weight of single fruit of melon increased by 20.3%, and the contents of fruit soluble sugar, soluble solids, soluble protein, sucrose, glucose, etc. increased significantly, sucrose synthase and sucrose phosphate synthase activities had been significantly improved. The study found that mixing proper amount of rice husk ash can effectively improve the physical and chemical properties of cultivation matrix, observably increase the photosynthesis ability of melon leaves, and improve the quality of melon fruit. The mixture matrix formula with a volume ratio of 2∶4 between rice husk ash and commercial finished cultivation substrate was the most suitable one, can replace the traditional substrate for melon cultivation.