State feedback exact linearization method in Buck converters have been widely recognized in the domestic, and it achieved a good control effect, but because the method is based on the accurate modeling, so when the model of controlled object is not accurate enough or circuit parameters in the application are changed, state feedback exact linearization method will be difficult to achieve the ideal control effect. In this paper we use the based on data-driven model-free adaptive controller (MFAC) on Buck Converter Applications for the first time. We analyzed the output characteristic of model-free adaptive control and the state feedback when load changes by simulation. Through the experimental platform of practical, we compared MFAC and the state feedback. Results show that, when the circuit parameter varies in a large range, MFAC has better robustness and resistance mismatch capability, high steady accuracy.