The invention discloses a cooling method of a heat insulation internal combustion engine and a light-heat insulation internal combustion engine. The exhaust temperatures of the internal combustion engines are acquired to determine the water spray quantities to inner cavities of cylinders of the internal combustion engines so as to realize the cooling of the internal combustion engines; water spray devices are connected with temperature detecting devices and control devices; the quantitative water spraying is realized through the control devices; cooling substances are water or water solvents; heat insulation materials of the cylinders are ceramics; light insulation materials on the inner surfaces of the cylinders are aluminum alloys, or are plated with silver; the water spray masses are determined according to the exhaust temperatures in the operation of the internal combustion engines, and are 0-3.2 times of the oil spray masses; the exhaust temperatures can be reduced through the water spraying; when the compression ratio is 7-12, the exhaust temperatures of the cylinders are reduced to 900-750 DEG C; when the compression ratio is 14-24, the exhaust temperatures of the cylinders are reduced to 700-550 DEG C; and the aluminum alloy inner walls of the cylinders or the silver plated inner walls of the cylinders can reduce the temperatures of air suction strokes and compression strokes. The cooling method has the advantage of effectively reducing the working temperatures of the cylinders of the heat insulation internal combustion engine and the light-heat insulation internal combustion engine so as to enable the heat insulation internal combustion engine and the light-heat insulation internal combustion engine to be applied.