The utility model provides a main transformer falling film type heat exchange device with a photovoltaic conversion function. The device comprises a transformer oil flow cooling circulating system, a refrigerant medium circulating system and a control system, and energy is provided through a photovoltaic conversion system with a solar energy storage function. According to the device, heat exchange is carried out through a falling film tube wall of a falling film type evaporator, the control system can automatically control transformer oil in the tube pass of the falling film type evaporator, film-shaped oil is formed and flows down along the inner wall of a falling film tube, the heat exchange effect is improved, work of a variable-frequency refrigerating compressor and a variable-frequency oil pump can be automatically controlled according to the oil temperature in a transformer body, and the optimal value of a main transformer winding and oil flow temperature difference is always kept. The clean, efficient and safe energy such as solar energy is fully used as power of normal work, the main transformer falling film type heat exchange device has the advantages that energy is saved, environment protection is achieved, the size of equipment is small, the use amount of oil is little, maintenance is little and overall operation is economical, copper and iron loss of a main transformer can be greatly reduced, overflow capacity and short-circuit current resistance of the main transformer are improved, the service life of the main transformer is prolonged, and safety operation of the main transformer can be well guaranteed.