Abstract: A wheel loader, having a higher acceleration and an energy-saving performance, as well as a higher traveling and working efficiency, includes: a traveling system, having an engine (1) as a driving power source; and a hydraulic working system, operated by receiving pressurized oil from a hydraulic pump (81, 82) having the engine (1) as a driving power source. The hydraulic pump can be a variable displacement hydraulic pump (81) or the combination of a fixed displacement pump (82) and an unloader valve (821). The displacement volume (V) of the variable displacement hydraulic pump (81) can be changed from a maximum (Vmax) to a minimum (Vmin) when the hydraulic working system is changed to be in a neutral (non-operating) condition (Wo). The useful output of the hydraulic pump (81,82) can be changed from a maximum (Vmax) to a minimum (Vmin) when a vehicle speed is greater than a specified vehicle speed, or the speed gear is changed from a low side speed gear to a high side speed gear.