The invention discloses a piston rotation type internal combustion engine. An annular air cylinder with the circular inner section is formed by two annular cylinder bodies with the semicircular inner sections. Two pairs of pistons are arranged in the cylinder bodies. Two noncircular gears and two pairs of pistons are assembled into a whole through a transmission mechanism to be engaged with two eccentric gears on the same power output shaft, and power is output through an eccentric gear shaft. A special piston ring lubricating mechanism and a special piston cooling system are further arranged. Cylinder sleeves made of heat resisting materials are adopted in the parts, at the combustion expansion acting section part, of the cylinder bodies, the sections of cylinder sleeves are isolated from other machine bodies through heat isolation materials, accordingly, the parts, at the combustion acting section, of the cylinder bodies are constantly kept at the high-temperature state, combustion of mixed gas is better facilitated, combustion of the mixed gas is more rapid and more thorough, and the heat efficiency is higher; and various design schemes of serial connection and parallel connection combinations of multiple cylinder bodies and various arrangement schemes of engagement of the noncircular gears and the eccentric gears exist, efficiency is higher, and the output power is larger.