A back and abdomen exercising apparatus includes a base and a back rest, and the backrest is provided at the rear portion of the base. The backrest is mounted on the base with two resilient members. A user sits on the base with back abutting against the backrest and presses the backrest backward, the resilient members provide a biasing force against the user. During the process, the muscle back and abdomen of the user is exercised and trained. In addition, the exercising apparatus has simple components, a simple operation method, a small size and light, and is convenient to carry.