This study investigates the dynamic event-triggered (DET) model-free adaptive tracking control (DET-MFATC) problem for nonlinear systems with consideration of denial-of-service (DoS) attacks and round-trip time (RTT) delays. Firstly, we introduce an attack compensation mechanism for the sake of reducing the effects of DoS attacks. At the same time, a network predictive delay compensation mechanism is proposed for compensating the effects of RTT delays caused by packet dropouts, network time-delay and packet disorders. What’s more, the DET method is developed to save communication resources. The nonlinear system is represented by an equivalent data model where the nonlinear characteristics are expressed as pseudo-partial derivative (PPD) parameters. The designed DET-MFATC algorithm can guarantee the security tracking control problem only using input and output (I/O) data. In the end, simulation results clearly certify the effectiveness of the presented algorithm.