The present invention offers a type of chair cushion and its supporting structure, and belongs to the technical field of chair manufacture. It solves the problem of unreasonable design in prior art. The chair cushion and its supporting structure comprise a pair of side boards and a bottom board. The undersides of the pair of side boards are provided at both sides of the bottom board to form a mounting cavity in which are provided several elastic supporting components. Each elastic supporting component includes several vertical springs of identical size and shape and a first flexible cladding. All springs in each elastic supporting components are arranged in at least one row and cladded in the first flexible cladding. The advantages of the chair cushion and its supporting structure lie in that the elastic supporting components formed by the first flexible cladding that clads at least one row of springs promote the strength for supporting person's hip weight on the seat. Due to the promoted buffer capacity, the protection role is enhanced to the person sitting in the seat.