The utility model discloses a front input axle used for a heavy type through type drive axle. The front input axle used for the heavy type through type drive axle comprises a axle body, the axle body is provided with an axial oil duct, a radial oil inlet hole and a radial oil outlet hole, the radial oil inlet hole and the radial oil outlet hole are communicated with the axial oil duct, and the radial oil inlet hole is arranged above the radial oil outlet hole. Lubricating oil which is stored in a axle case swell flows into an oil duct of the front input axle and then into an inter-axle differential to lubricate a planet half axle gear inside, so that service life of a gear is prolonged. Meanwhile, Gear oil does not need to be filled between axles, so that a structure of a whole axle is optimized, namely, the size between an input flange surface and the center of the axle case is shortened, and the structure of the whole axle and arrangement of a whole vehicle are compact.