Provided is an integrated steep slope collapse simulation system including: a base; a tower provided at one end of the base; a soil tank structure having one side being connected to the tower so that the soil tank structure is inclined, the soil tank structure being filled with soil, and the soil being rammed; a work platform provided with a working stand moving along the base and moving up and down; a soil moving device supplying soil to an interior of the soil tank structure; an artificial rainfall device provided above the soil tank structure, the artificial rainfall device injecting water downward toward the soil rammed inside the soil tank structure; and an underground water reproduction device injecting water upward through the bottom surface of the soil tank structure from the underside of the soil rammed in the soil tank structure. There is an effect that it is possible to accurately analyze an actual behavior of soil in the natural environment.