Cycling is an integrated effect process of several physical forces including gravity, support force, a ir resistance and ground friction. For the changes of air speed and r iding road, the stress processes of outdoors road c ycling are more complex. In the process of riding, how to provide r ealistic scenes like the real scene, not only in th e visual, but also to achieve the consistency of exercise bicycle ridi ng load and actual riding feeling is more important . Based on the analysis of the stress, the research constructed th e mathematical model of cycling process of road bic ycle and studied the features and laws under different ridin g conditions by solving the model. The findings are follows,. Firstly, speed should be maintained at around 13m/s in the relatively flat road riding; Secondly, in t he continuous rolling road, we can accelerate the riding speed if the distance is short, we should reduce the speed if it is longer; Thirdly, in rated power uphill and downhill riding, speed has little effected when there are the uphil l section with smaller inclined angle and downhill section with la rger inclined angle; Lastly, spring 180m can reach speed peak, while the best distance to the sprint stage is180~2 20m. These parameters will be used for the control system of exercise bicycle.