NOVELTY - Controlling marsh gas tank environment by polycondensation light, comprises collecting light by a light collection device and transmitting by the light transmission device, arranging a light shunting switch in the light transmission device, controlling light energy transmitted into the marsh gas tank, and converting the light energy into heat energy at a terminal of a light transmission channel, heating biogas slurry in the marsh gas tank, using the temperature sensor for detecting the temperature in the biogas slurry, and detecting the marsh gas in the marsh gas tank by a pressure sensor.    USE - The method is useful for controlling marsh gas tank environment by polycondensation light (claimed).    DETAILED DESCRIPTION - Controlling marsh gas tank environment by polycondensation light, comprises using a marsh gas tank, a light transmission device, a light control device, a pressure sensor, a temperature sensor and a light energy-heat energy conversion device; collecting light by a light collection device and transmitting by the light transmission device for transmitting light through the light collecting device, arranging a light shunting switch in the light transmission device, controlling light energy transmitted into the marsh gas tank, and converting the light energy into heat energy at a terminal of a light transmission channel; heating biogas slurry in the marsh gas tank by: (a) directly heating biogas slurry in the marsh gas tank by utilizing a corrosion-resistant metal structure to achieve fast heat conduction and utilizing a non-metallic structure to achieve slow heat conduction, and (b) heating marsh gas tank shell body to improve the temperature of the biogas slurry in the marsh gas tank by thermal transmission between the biogas slurry and the shell body; using the temperature sensor for detecting the temperature in the biogas slurry, controlling light flow according to the light shunt switch and providing suitable microbial fermentation temperature environment for the biogas slurry; and detecting the biogas of biogas slurry in the marsh gas tank by a pressure sensor to ensure the tank is under safe biogas pressure, and controlling the light flow according to the light shunting switch.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of the device for controlling marsh gas tank environment by polycondensation light.    Integrated polycondensation function unit (1)    Light shunting switch (2)    Light transmission channel (3)    Marsh gas tank (4)    Light energy-heat energy conversion device (5)