Aiming at the problem of low precision and hysteresis for the agricultural chassis in the hilly area, a pre-detection active leveling method was proposed to detect the ground situation ahead of the road and determine how to implement the leveling action and actively adjust the body while tilting. It can actively prevent, reduce or avoid the body tilt during driving on rough terrain. An agricultural vehicle pre-detection active leveling chassis with Y-shaped adjustable suspension as the leveling mechanism was designed. The chassis suspension adjustment and pre-detection leveling parameters, load capacity and leveling speed and leveling execution strategy were analyzed and calculated. The analytical calculations showed that the chassis can be leveled by the height adjustment of each Y-shaped adjustable suspension. The prototype was developed and tested on the rugged ground in the outdoor test field. The test results showed that the active predetection leveling chassis of the hilly mountain was controlled well that the accuracy of both roll angle and pitch angle just was within 0.5°, verifying the pre-detection active leveling method and the feasibility of the active leveling chassis for agricultural pre-detecting in hilly mountains, and providing theoretical basis and experimental reference for the promotion and application of agricultural chassis in hilly mountainous areas，which had high practical value in the future.