The adaptive event-triggered control problem for a class of uncertain high-order pure feedback nonlinear systems (HOPFNSs) is considered. Different from the traditional backstepping method, a new high-order backstepping method is proposed based on the high-order fully actuated (HOFA) system approaches to design the adaptive event-triggered control law, which has the significant advantages of simple structure, high degree of freedom, and easy to realize. The high-order backstepping method does not need to transform the HOPFNSs into the first-order systems, which is more efficient and significantly reduces design complexity. It is proved that the adaptive event-triggered controller makes all the signals of the system bounded and save the energy in signal transmission. A simulation example is performed to verify the effectiveness of the control strategy.