The soil micro-environment in the root zone of "soil-root system-microorganism and enzyme" is a complicated system. The interaction of various factors determines the material exchange and energy flow between the soil and the ground plant, and ultimately affects the crop growth and yield. Soil moisture is the most important factor, which effects root-zoon soil microbial environment. In this experiment, the muskmelon cultivar"Western Region No. 1" was used as the test material for pot cultivation under the same environmental conditions in the solar greenhouse. By means of drip irrigation, changing the soil microbial environment, we set up five muskmelon treatments. Under different treatments, the upper and lower limits of irrigation were preset in the four main periods of muskmelon growth. The results showed that the morphological indexes of the muskmelon have an increasing trend with the rise in irrigation upper limit in the same growth period. By comparing the effects of different irrigation treatments on the external morphological indexes and internal physiological indexes of muskmelons, we find the relatively suitable irrigation treatment for greenhouse muskmelon growth: T3 treatment, with 60% -70% germination stage, 70% -80% tendril elongation stage, 80%-90% flowering stage, and 60% -70% fruit setting stage.