The invention relates to a control method making full use of waste heat for a building type combined cooling, heating and power system, and belongs to the technical field of operation control. When user cooling/heating load is lower than the cooling/heating capacity of an absorption refrigeration/heating unit, surplus cold/heat energy is introduced into a cold/heat storage tank to be subjected toenergy storage, a water tank is used for supplementing water to the system, and when the liquid level of the cold/heat storage tank exceeds a highest liquid level, exhaust gas into the absorption refrigeration/heating unit is adjusted to meet the user cooling/heating load; and when the user cooling/heating load exceeds the cooling/heating capacity of the absorption refrigeration/heating unit, cold/heat energy in the cold/heat storage tank is released to the system, the water tank is used for recycling part of returned water, and when the liquid level of the cold/heat storage tank is lower thana lowest liquid level, an electrical refrigeration unit is used to supplement cold energy, or a gas-fired hot water boiler is used to supplement heat energy. According to the method, the waste heat of a gas genset can be effectively utilized, the comprehensive energy utilization efficiency of the system is improved, so that the method is suitable for design and operation control procedures of thebuilding type combined cooling, heating and power system.