Abstract: In response to the problems such as level discretization, non-linearity of braking rate and insufficient algorithm reliability faced by the automatic driving system of high-speed trains in operation control, in order to enhance the reliability and computational efficiency of the control strategy, a computer model for the nonlinear braking rate of trains is established, and the level projection technology is introduced. However, due to the extensive calculations required for various level combinations in level projection technology, the reliability of the algorithm often struggles to meet the high reliability standards demanded by train control systems. To address this, a "definite solution" condition-based judgment method is proposed. This method can quickly determine whether there is a solution for each level combination. When combined with algorithm optimization strategies, it can reduce computational load by 90%. Engineering application results demonstrate the effectiveness of the proposed control strategy and the reliability of the algorithm, making them suitable for application in various train automatic driving systems.