A protection device of self-propelled vehicle including a main body, a frame body, and at least two pivoting members is provided. The main body has a rail or a moving block, and the frame body has a moving block or a rail. The frame body moves on a plane relative to the main body via the moving block being removably coupled to the rail. The two pivoting members being removably pivoted to the main body and the frame body along two normal lines of the plane respectively. The frame body is forced to be rotated on the plane with one of the two pivoting members relative to the main body.