Foundation pit supporting structure

The utility model relates to the technical field of building facilities, and discloses a foundation pit supporting structure which comprises a supporting plate. A diagonal bracing part; the floating block can freely slide up and down in the sliding cavity; the pull rod is used for driving the floating block to move upwards; the detection pin is obliquely arranged on the supporting plate in a penetrating mode, a sliding hole for the detection pin to freely pass through is formed in the supporting plate, and the detection pin is connected with the floating block through a connecting unit, so that when the floating block moves upwards in a sliding cavity, the detection pin is driven to move towards the outer side of the supporting plate. Through the arrangement of the pull rod, the floating block and the detection pin, when the supporting plate is inserted into the foundation pit, the pull rod is pulled upwards, then the pull rod drives the detection pin to obliquely slide upwards and penetrate out of the suppor