Inner top type supporting structure for foundation pit supporting

The utility model discloses an inner top type supporting structure for supporting a foundation pit, which comprises an inner top base frame and a downward folding slide rail, and the downward folding slide rail is fixedly connected to the lower part of the inner top base frame; a driven rotating bevel gear ring is rotationally arranged in the middle of the inner jacking base frame, a driving assembly used for driving the driven rotating bevel gear ring to rotate is fixedly connected to the upper portion of the inner jacking base frame, and four annularly-distributed support rods are fixedly connected to the lower portion of the inner jacking base frame; the number of the downward-folding sliding rails is four, the upper ends of the four downward-folding sliding rails are fixedly connected with the bottom of the inner top base frame, linkage sliding rods are slidably connected to the middles of the downward-folding sliding rails, inner supporting plates are fixedly connected to the lower ends of the linkage sl