An ultra-high speed space laser communication receiving system with multi-core preamplifier belongs to the technical field of free laser communication. In order to solve the problems of low coupling efficiency, low receiving optical power and low communication rate of the coherent receiving system based on a photon lantern, a receiving antenna is connected with a multi-core single-mode optical fiber, and a multi-core single-mode optical fiber is connected with a multi-core preamplifier. The multi-core preamplifier and a port a the plurality of optical circulators are connected. A port b of theoptical circulator and a port a of the next optical circulator are connected with a single-mode fiber having a reflective fiber Bragg grating. Port c of each optical circulator is connected with thephoton lantern by a multi-channel single-mode optical fiber. The photon lantern is connected to an avalanche photodetector; The output port of avalanche photodetector is connected with demodulator. The system has a wide application prospect in space laser communication and other fields.