Abstract: Taking Lovol Oubao medium tractor and Dongfanghong large tractor as examples，relationship between tractor speed and rotary tillage quality was analyzed.Results showed that rotary tillage quality was ensured only tractor in a certain range of walking speed.Taking Haofeng rotary tiller as examples，internal transmission of gearbox for rotary tiller was analyzed.Results showed that rotation speed of rotary blade shaft could be increased，so as to improve efficiency of rotary tilling by changing gear ratio of gearbox.But the effect was not obvious.The most effective way to improve efficiency of rotary tillage was to select wide rotary tiller as far as possible on the basis of not affecting operation quality.