This patent provides a phone case. The backplate and side plate constitute the accommodating cavity of phone, and it is the amplifying cavity; Reinforcing rib is equipped at the edge of back plate. It may protrude to the inside and butt against the mobile phone frame. When the phone falls, the reinforcing rib or side plate separates the phone screen or phone body from the ground, cushions the impact of the ground and transfers the impact force to the phone frame, to avoid that the impact force directly acts on the phone screen and body. It has the great anti-falling effect.