To address the problems of limited network resources, load disturbances and transmission delays affecting the control performance of networked permanent magnet synchronous motor (PMSM) systems, an adaptive periodic event-triggered control strategy is proposed. Firstly, based on conventional periodic event-triggered H∞ control, the fixed triggering threshold is replaced with an adaptive threshold that varies with the system state information, and different weighting matrices are used instead of identical ones. In this way, an adaptive periodic event-triggered control (APETC) strategy is developed to further enhance the flexibility and efficiency of the triggering mechanism. Simultaneously, to more accurately characterize the system behavior, a mathematical model of the networked PMSM system considering APETC and transmission delay is established. Second, based on Lyapunov stability theory and the concept of the free weight matrix, deriving the sufficient conditions for the system asymptotic stability and satisfaction of the H∞ performance. Based on these results, a co-design method for the APETC and H∞ controller is developed, which effectively alleviates network congestion and improves the utilization of network resources. Finally, the effectiveness and superiority of the proposed method are demonstrated through comparative experiments, including sudden change operation, loaded operation, and variable-speed operation on a YXSPACE-SP2000 rapid prototype control platform. The experimental results show that, compared with the traditional periodic event-triggered control, the proposed APETC can significantly reduce unnecessary data transmissions while maintaining control performance. Moreover, relative to the PI control, the designed H∞ control exhibits a markedly faster dynamic response and stronger disturbance rejection. These results verify the effectiveness and superiority of the proposed method in improving network resource utilization and enhancing system robustness.