The large briquette machine consists of transmission motor, synchronous gear reducer, preloading device, main machine device,hydraulic system, belt conveyor and electronic control. Among them, the synchronous structure adopted by the transmission system makes the main engine transmission realize good design,manufacture, use and maintenance. The hydraulic device adopts the structure of small cylinder body and large tension force, thus realizing the purpose of reducing the quality of the whole machine and reducing the consumption of steel. The ball pressing roller adopts a combined structure, which realizes that vulnerable spare parts can be replaced on site, thus reducing the loss caused by the shutdown of the production line.