The net chamber experiment was conducted to study soil evaporation intensity with degradable hydromulching. The results showed that degradable hydromulching inhibited soil evaporation process. According to hydromulching ingredients, the mechanisms were divided into sealing effect and retaining effect. Both effects played a leading role at different stages, and the intensity varied with the composition ratio of hydromulching. Different processing with Matlab kinetic equation showed that hydromulching could reduce maximum evaporation and extend its half-life with reasonable amount.