The invention relates to an automatic construction device for net hanging and spray-seeding on a highway. The automatic construction device comprises a vehicle body, a drilling and net hanging mechanism, an auxiliary lifting mechanism, a stirring system and a vehicle body power device, wherein an operation room and travelling wheels are arranged on the vehicle body; and the vehicle body power device is composed of an engine, a gearbox, and driving axles connected with diving shafts of the traveling wheels. The whole automatic construction device can complete the work of net hanging and spray-seeding, and the production efficiency of assembly line work is high. The whole working process of the automatic construction device is controlled mechanically, so that the performance is reliable; as the whole automatic construction device adopts the design of a vehicle, the mobility is high, and the automatic construction device can quickly and easily arrive at a workplace; and as manual operation is replaced by mechanical operation, the construction cost is greatly reduced.