To address the challenges of multi-dimensional performance optimization and task adaptation for MAC protocols in dynamic network environments, this study proposed a software-defined reconfigurable MAC protocol architecture and algorithm. To overcome the limitation of isolated performance optimization in existing adaptive MAC protocol methods, we established a closed-loop mapping model that correlates network characteristics, task requirements, and protocol performance, thereby achieving balanced multi-dimensional performance optimization. For the problem of inaccurate network load model, we designed a distributed observable load model to provide support for the reconfiguration algorithm. Furthermore, the study implemented multi-level flexible MAC protocol reconfiguration through software-defined approaches, overcoming the limitations of hardware-coupled protocols. Simulation results demonstrated that the proposed reconfiguration mechanism balanced multiple performance dimensions and diverse task requirements, while dynamically selecting the optimal MAC protocol. This study provides a systematic solution for achieving adaptive reconfiguration of MAC protocols in wireless ad hoc networks.