Abstract: The step calculation is a crucial part in the tool path planning of five-axis machining. At present, the commonly used step length algorithms are mainly equal parameter step algorithm and constant chord error step algorithm. The constant chord error step algorithm adopts the method of approximate substitution to calculate the step length. Therefore, the traditional constant chord error step algorithm will inevitably produce certain errors, resulting in a decline in the quality of the surface machining. In order to solve the above problems, this paper will add accurate chord error checking calculation on the basis of the traditional constant chord error step algorithm, and then use a one-dimensional linear search algorithm to adjust the position of the next cutter-contact point. The simulation results show that: under the condition that the allowable chord error is the same, the algorithm in this paper has better machining efficiency than the equal parameter step algorithm and better machining accuracy than the constant chord error step algorithm.