The invention relates to a modular integrated assembly type floor and a construction method thereof. The modular integrated assembly type floor comprises a base layer and a surface layer, a waterprooflayer is arranged between the base layer and the surface layer, the base layer comprises a pressure-bearing module and an adjustable support matched with the pressure-bearing module, the pressure-bearing module is square, four corners of the pressure-bearing module are provided with fan-shaped bumps, the adjustable support is formed by assembling a jacking with a pressure-bearing steel board at the upper part, a plurality of reinforcing rib boards connected with the jacking, lengthened nuts arranged in the reinforcing rib boards and welded and fixed to the center of the lower part of the jacking, and bolts matched with the lengthened nuts. The modular integrated assembly type floor can effectively solve the common defects of unstable quality, long construction period, low work efficiency,high energy consumption, high cost, environmental pollution and difficulty in maintenance and reconstruction of buried pipelines in current building ground construction.