The natural gas temperature and pressure regulating system based on recovering pressure energy and absorbing heat from ultralow temperature ambient environment. A pressure driven heating system of pipeline natural gas pressure regulation or liquid natural gas regasification process. This system adopts vortex tube, ambient air heat exchanger and ejector that constitute the pressure driven heating unit to replace the existing heater. The two kinds of pressure driving devices of an ejector and a vortex tube are adopted, transmit the low temperature NG at the cold end of the vortex tube into the ambient air heat exchanger to absorb heat from the ambient continuously; at the same time, make temperature of the gas from the hot end of the vortex tube increase to meet the required temperature of pipeline directly, then achieve the purpose of no heater energy consumed.