A parallel motion heat energy power machine and a working method thereof, includes a heat collector, an insulating pipe, a gasification reactor, an atomizer, a cylinder, a piston, a piston ring, an automatic exhaust valve, a cooler, a liquid storage tank, a pressure pump, a push-pull rod, an insulating layer, and a housing. The two cylinders are oppositely arranged on the housing in parallel. The piston is arranged inside the cylinder. The piston is provided with the piston ring. The pistons are arranged on both ends of the push-pull rod. The heat collector is connected to the gasification reactor through the insulating pipe. The atomizer is arranged on the air inlet end of the gasification reactor. The parallel motion heat energy power machine and working method thereof has a high heat-energy conversion efficiency. It is energy-saving, environmentally friendly, and less noisy.