These series products are middle hp tractors with advanced performances at present. It has the characteristics of powerful engine, high transmission efficiency, big traction, low fuel consumption, high adaptability, compact structure and easy operation and maintenance. Joggling sleeve is equipped for its gearing shifting. 4×(2+1) gear shifts, good reliability, reasonable speed distribution, two stage clutch, two rev. PTO according with international standard, hydraulic output interface and adjustable tread and mechanical or hydraulic steering are equipped with it for user's selection. Model AOYE 424/464 as four wheel drive tractor is designed by installing a front drive axle on Model AOYE 420/424. Its traction is improved on a large scale and is more suitable to mountain areas and muddy roads.