【Objective】 To study pass-ability of small multi-function chassis for intercropping in Southwest hills.【Method】 The mathematical model was established by evaluating related geometric parameters of vehicle contour and analyzing the Southwest mountainous areas marked by intercropping cultivation agronomic angle and terrain features.【Result and conclusion】 Parametric test results showed that the theoretical and measured values were consistent. The highest vertical obstacles and the widest trench were 190 and 280 mm respectively. Chassis prototype climbing ability tests results showed that the multifunctional chassis prototype had a good climbing ability and it showed a good passing performance to climb under undulating ground conditions.