The invention discloses a cast-in-place and prefabricated combined type portable communication tower ground foundation and a construction method. According to the cast-in-place and prefabricated combined type portable communication tower ground foundation and the construction method, the problems that the construction period is long, the transportation, assembling and disassembling cost is high, connection reliability between prefabricated elements is low, the installation precision of the prefabricated elements is not ensured, and the installation and alignment are difficult are solved. The cast-in-place and prefabricated combined type portable communication tower ground foundation comprises a model stabilizing frame, prefabricated blocks and cast-in-place concrete arranged on the left and right sides of the prefabricated blocks. Embedded parts for installing a communication tower are arranged in the prefabricated block. The prefabricated block and the cast-in-place concrete are laidwith bar-mat reinforcement. The prefabricated blocks are exposed on left and right sides of the bar-mat reinforcement on the prefabricated blocks, and the prefabricated blocks are connected with the bar-mat reinforcement in the cast-in-place concrete. A plurality of transverse embedded poles and a plurality of longitudinal embedded poles are embedded in the prefabricated blocks. The prefabricatedblocks are exposed at the ends of the transverse embedded poles and the longitudinal embedded poles. Steel beams are connected between the ends of the transverse embedded poles and the longitudinal edge of the model stabilizing frame, the steel beams are poured into the cast-in-place concrete, and the ends of the longitudinal embedded poles are detachably connected to the transverse edge of the model stabilizing frame.