The invention discloses a novel combined cooling, heating and power system utilizing internal combustion engine waste heat and a working method thereof. According to the technical scheme, the exhaustgas of an internal combustion engine releases energy through a waste heat boiler HRG to drive an organic Rankine cycle power generation system to circularly generate electricity; except that the exhaust gas of the internal combustion engine releases the energy through the waste heat boiler HRG to drive the organic Rankine cycle power generation system to circularly generate electricity, the remaining energy is divided into two branches, namely, a first branch and a second branch; the first branch is used for driving an ammonia absorption type refrigeration sub-cycle system to carry out cycle refrigeration; and the second branch, the internal combustion engine cylinder sleeve water and the organic Rankine cycle power generation system provide heat for a heat supply system. The system has the advantages that the organic Rankine cycle, the ammonia water power cycle and the heat supply device are coupled and integrated so that the cycle acting amount, the refrigerating capacity and the heat supply quantity can be increased, and the efficiency of the combined system can be improved.