A downhole gas-liquid separation device comprises a barrel-shaped body, and a positioning wheel is fixedly installed in the body. A rotatable swirling wheel is installed on the positioning wheel and provided with spiral wheel blades, and the positioning wheel is provided with fluid channels. A lower connector is connected to the body, a diverting joint is arranged at the inner end, located in an inner cavity of the body, of the lower connector, a gas outlet channel is formed in the center of the diverting joint in a coaxial mode, and the outer side of the diverting joint is provided with liquid drainage channels. An interval is formed between the swirling wheel and the diverting joint. The downhole gas-liquid separation device is small in part number, simple in structure and lower in cost; the swirling wheel is driven to rotate when liquid passes through the swirling wheel to enable the liquid to generate centrifugal force and swirlingly flow in the inner cavity in the mode of being attached to the wall, the liquid in gas is gathered to the center, and then the liquid and the gas flow out through the liquid drainage channels formed in the outer side and the gas outlet channel formed in the center respectively, so that gas and liquid separation is achieved; accordingly, the liquid sent to a motor does not contain the gas, damage to the motor is avoided, and the service life of the motor is prolonged.