Provided is direct driving vertical axis current power generation devices for an underwater vehicle. Two vertical axis current power generation devices are arranged on an underwater vehicle shell, and the installation directions of the two vertical axis current power generation devices are opposite. Generators are fixedly arranged in central shafts through winding stators. Threes blades are arranged at the top end of a telescopic mechanism in each vertical axis current power generation device, and the blades rotate around the central shafts under the impact of coming flows and generate tangential force driving rotating shafts to rotate, so that the blades, the telescopic mechanisms and power generation device supports rotate around the longitudinal axis of the underwater vehicle to drive inner gears connected the impeller shells to rotate and further drive outer gears and the power generators to rotate, and kinetic energy of ocean current is converted into electric energy used by the underwater vehicle. By means of the direct driving vertical axis current power generation devices for the underwater vehicle, energy supply of the underwater vehicle is achieved, the working time of the underwater vehicle is prolonged, and the cost is saved.