904 type tractor is Dongfeng Agricultural Machinery Group is a relatively mature product, the chassis was designed from the beginning with the design margin, prepared for the development of new models. Found in the process of long-term use, the chassis structure strength is good, so I hope to develop type 1254 tractor chassis on the basis of. In order to reduce design risk, first using the finite element method to calculate 904 type tractor chassis, find out the weak links of chassis design and put forward the improvement scheme. On this basis, puts forward the design scheme of 1254 type of tractor chassis, and the finite element calculation, to ensure reliability design scheme. Design 1254 type tractor chassis height inherited parts of 904 type tractor chassis, only the redesign of the front bracket and the rear axle housing, improve the power of different period of tractor parts commonality and interchangeability, conducive to series production enterprises. Check on the analysis of 1254 type of tractor chassis, on the base of reviewing the various parts of structure strength, first proposed the evaluation index of contact pressure, contact between different parts of the pressure distribution on the surface, on the effects of connection stiffness between parts. The main research contents of this paper: according to 904 type tractor chassis structure, set up the geometric model of tractor chassis using the SolidWorks software, carries on the grid division of the geometric model by using Hypermesh software professional, the finite element model. According to the foreign enterprise test method for tractor, identified seven calculating conditions this calculation, meet all kinds of harsh environment simulation of tractor may in reality, can effectively evaluate tractor chassis structure strength whether meet the design requirements, the finite element model of the structure strength analysis using ANSYS software, obtained stress distribution nephogram of the parts of the chassis the chassis, find out the weak parts of structure, the stress concentration is more serious parts (including a front bracket, clutch housing, final drive housing) were improved, the improved overall chassis rigidity is improved. Using the calculation conditions similar to the calculation and type 904 tractor chassis analysis, analysis of 1254 type tractor chassis, by analyzing the stress nephogram, found the rear axle housing type 1254 tractor exists the phenomenon of stress concentration, and gives the improved scheme, the improved stress concentration situation has improved; the connection stiffness between the poor after the discovery of the axle housing and clutch shell, put forward 2 kinds of schemes. Compressive stress distribution through the comparison of the improved contact, obtains the improvement scheme of 1 higher feasibility.