Tower crane bottom supporting structure

The utility model discloses a tower crane bottom supporting structure, and relates to the technical field of tower cranes. The device comprises four pre-embedded columns and four butt joint columns, the bottoms of the four butt joint columns are fixedly connected with butt joint head sets, the tops of the four pre-embedded columns are fixedly connected with butt joint base sets, and the butt joint columns and the pre-embedded columns are detachably connected through the butt joint base sets and the butt joint head sets. Fastening assemblies are connected to the outer walls of the four embedded columns in a clamped mode, and abutting mechanisms are connected to the tops of the fastening assemblies in a clamped mode. Through the arrangement of the fastening assembly and the abutting mechanism, the length between the angle seat and the adjusting plate can be adjusted through the second bolt assembly, so that fastening of tower cranes with different diameters within the adjusting range is facilitated, meanwhile,