The invention discloses an integrated integral forming light square cabin of resin-based composite material and a manufacturing method thereof, wherein the square cabin comprises a square cabin body,the inner part of the square cabin is provided with an accommodating space and is formed with a door, a window or a working hole, the square cabin body comprises: an integral frame, wherein the integral frame provides strength of the square cabin body and an installation support; an inner skin, wherein the inner skin is mounted on the inner surface of the integral frame; an outer skin, wherein theexternal skin is arranged on the outer surface of the integral frame; a sandwich layer, wherein the sandwich layer is arranged on the integral frame and arranged between the inner skin and the outerskin and is respectively connected with the inner skin and the outer skin; a resin filling layer, wherein the resin filling layer is positioned between the inner skin and the outer skin and runs through the sandwich layer and the integral frame. The method solves the problems of poor sealing performance and low stability and strength of a prior square cabin during the transportation and usage processes, improves the sealing performance, the stability and the strength of the square cabin, and has obvious weight reduction effect.