The invention provides a cold and hot electric and pure water four-combined supply system and a combined supply method. A gas turbine power generation subsystem is configured to apply work and generate electricity of energy generated by mixing and combusting pre-cooled air and natural gas; a multi-effect distillation subsystem is configured to heat condensate water into superheated steam by utilizing heat of a flue gas discharged by the gas turbine power generation subsystem, the superheated steam is used for heating a inlet liquid, and a formed distillation liquid is used as pure water; a composite power generation refrigeration subsystem is configured to heat an ORC working medium by utilizing heat of the flue gas discharged by the multi-effect distillation subsystem, the heated ORC working medium is used for expanding to apply the work and generate electricity, the ORC working medium which applies the work further releases heat and condenses to generate cold water; and a heat supplysubsystem is configured to heat the heat of the flue gas discharged by the composite power generation refrigeration subsystem to form domestic hot water. The cold and hot electric and pure water four-connection system can be used for efficiently and stepped utilization of exhaust waste heat and residual pressure, the comprehensive utilization efficiency of primary energy is high, and the system and the method is environment-friendly.