190～210 kg/m3。The basic structure and work principle of large rectangular baler were introduced. To satisfy the bundling compression property of maize straw and the load system require of burning straw generate electricity, gearbox, materiel collect and feed system, mechanical pre-compressing unit, baler plunger and hydraulic control system were design and computed. Collect and feed parameter, second pre-compressing principle and hydraulic control system were reasonably adopted to ensure the work dependability. The result indicated that the fully bale rate of 4YF-1300 large rectangular baler can achieve 97.2%, the regular bale percent is 94.4%, and bale density can achieve 190～210 kg/m3, which can satisfy the performance request of large rectangular baler.