[Objective] The effects of litter cover on soil evaporation in the Rhododendron delavayi forest in Baili azalea scenic area were studied, in order to provide a scientific basis for the function of water conservation under the forest.[Methods] According to the theory of soil evaporation, a self-made micro evaporation and infiltration device was used to conduct the simulation experiment. The existing status of litter under the Baili rhododendron forest was taken as a reference, to study the effect of litter with different mass and different proportion on the inhibition of soil evaporation.[Results] The evaporation of soil water decreased with the increase of litter mass at different decomposition degrees and with the same litter coverage ratio. The evaporation of soil moisture decreased with the decrease of soil moisture contents. When the moisture contents decreased by 0.5%, the evaporation of soil moisture with litter cover of 60 g, 30 g and 15 g decreased by 0.11 g, 0.49 g and 1.23 g, respectively. When the cover quality of litter was the same, the inhibition of litter with different decomposition degrees on soil water evaporation was different, which showed as follows:undecomposed > semi-decomposed > decomposed.[Conclusion] The more litter cover, the greater the inhibition of soil evaporation; the lower the decomposition degree of litter, the better the inhibition of soil evaporation.