The present disclosure provides a flexible suit and a flexible system for rehabilitation training of a human leg. The flexible suit includes a first hip joint motion assembly, a first knee joint motion assembly and a first ankle joint motion assembly, a first end of the first knee joint motion assembly is connected with the first hip joint motion assembly, a second end of the first knee joint motion assembly is connected with the first ankle joint motion assembly, the first hip joint motion assembly, the first knee joint motion assembly, and the first ankle joint motion assembly each includes a flexible mechanism, and at least one of a group consisting of the first hip joint motion assembly, the first knee joint motion assembly, and the first ankle joint motion assembly is configured to operate under gas drive.