The research of soil pressure distribution on the terraced field ridge of polyprophylene bags was undertaken with the test of soil pressure using the soil pressure boxes under artificial rainfall and the cause of slumping and bulging of retaining wall of terraced field with polypropylene bags in Qinba Mountain in Southern Shaanxi Province was explored.The results showed that the distribution curve of soil pressure on the terraced field ridge varied with different building conditions,and the heavy rain and continuous rain are the key factors of the collapse of the terraced field ridge.