The invention discloses a distributed energy source system for a natural gas purification plant and a technical method. The distributed energy source system comprises a fuel gas buffer tank, fuel gaspressure regulating equipment, a prime motor generator set, waste heat utilization equipment and a gas distributing cylinder. The fuel gas buffer tank, the fuel gas pressure regulating equipment, a prime motor generator set exhaust gas outlet, the waste heat utilization equipment, a first electrically operated valve and an inlet of the gas distributing cylinder are sequentially connected through pipelines. A first outlet of the gas distributing cylinder, a second electrically operated valve and a technical device are sequentially connected through pipelines. A second outlet of the gas distributing cylinder, a third electrically operated valve and a steam-type dual-effect absorption set are sequentially connected through pipelines. According to the distributed energy source system for the natural gas purification plant and the technical method, the requirements for cold, heat, electricity and sanitary hot water in the natural gas purification plant are effectively met through optimization and integration of an original technical system as well as gradient utilization of energy sources, the comprehensive utilization rate of the energy sources is increased and carbon emission is reduced.