The principle of the electric heating constant temperature incubator is to use artificial methods to create an artificial environment for the growth and reproduction of microorganisms, cells and bacteria in the incubator, such as controlling a certain temperature, humidity, gas, etc. The electric heating constant temperature incubator utilizes the phenomenon that solids, liquids, and gases expand and contract under the influence of temperature; under the condition of constant volume, the gas or vapor pressure changes due to different temperatures; the effect of thermoelectric effect; the resistance changes with the change of temperature change; the effect of thermal radiation, etc.