The invention relates to a six-stroke gasoline engine without an ignition system. Before air intake and compression of the engine, one air intake operation and one exhausting operation are added, cooling is performed for reducing the temperature of the interior of a cylinder at a time, and therefore, spontaneous combustion after gasoline spraying is avoided. After the two strokes of the engine are added, the revolution number of a crankshaft is increased by 360 degrees, the frequency that a piston passes through the starting and ending points is increased, accordingly, the mass of a flywheel of the engine is supposed to be increased by 1/3, and the engine is made to rotate more stably. As for the six-stroke engine and a four-stroke engine, the air distribution frequency of a camshaft needs to be changed, and the revolution number of the camshaft needs to be changed by 1/3, that is, the situation that working is applied once when the crankshaft rotates for two circles is changed to the situation that working is applied once when the crankshaft rotates for three circles.