Foundation pit supporting system and using method thereof

According to the foundation pit supporting system and the using method thereof, the foundation pit supporting system comprises outer baffles and transverse supports, longitudinal supporting rods are arranged on one side between the two opposite outer baffles respectively, the outer baffles and the longitudinal supporting rods are connected by installing a plurality of push-pull devices, and the transverse supports are installed between the two opposite longitudinal supporting rods; positioning devices are installed below the opposite sides of the longitudinal supporting rods on the two sides respectively, a supporting rod is installed between every two opposite positioning devices in an inserted and matched mode, and an inner baffle is installed between every two adjacent longitudinal supporting rods on each side. By means of the structure, the problems that the pipeline elevation adjustment construction efficiency is low, and the supporting structure cannot be taken out after concrete is hardened are solved.