Abstract: The present invention relates to a gas engine driven heat pump system (GHP) and, more particularly, to a gas engine driven heat pump system with a generator, the system including a generator that is driven to generate power by a gas engine in addition to driving a compressor by driving the gas engine, thereby using external power only in the early-state operation and, later, being able to drive a gas hat pump using self-power generated by the generator without using specific external power and to supply the power to an energy storage system (ESS) storing power and a power system requiring power in buildings, and the system further supplying hot water by restoring engine waste heat.