The electronic throttle of marine natural gas engines belongs to the category of nonlinear control. And the boundary of highorder sliding mode control is difficult to estimate. To address this issue, a novel adaptive high-order sliding mode control algorithm is proposed. An adaptive strategy based on the phase plane trajectory convergence process is designed. To increase the practicability of the control algorithm, the detection region is designed based on the adaptive algorithm. The control gain is dual-directional regulation by judging the relative position of the phase trajectory and the detection region to prevent the control accuracy from reducing due to excessive gain. Especially, a robust differentiator is used to estimate the derivative of the sliding variable in the controller. Finally, three test schemes are designed to compare the algorithm with the traditional high-order sliding mode algorithm. Experimental results show that the proposed algorithm can improve the system response speed by 35% and reduce the root mean square error by 37. 5% under the step signal. For the sinusoidal signal, the maximum steady-state error and the root mean square of steady-state error are reduced by 30% and 22% , respectively.