The invention relates to a double hill-climbing firefly algorithm-based spatial straightness assessment method. Firstly, a point direction form parameter equation can reflect a solving mathematical model of spatial straightness more intuitively. Secondly, measured data is obtained through a three-coordinate measurement machine, and an objective function of a problem is established through the mathematical model. Finally, the objective function is solved by adopting double hill-climbing firefly algorithms; the main steps include a parameter initialization process of the algorithm, firefly luciferin updating, movement probability calculation, firefly position updating, dynamic radius updating and the like; for the problems of low solving precision, relatively low convergence speed and the like of a standard firefly algorithm process, the double hill-climbing algorithms are simultaneously adopted for enhancing local optimization capability of the algorithm and increasing convergence speed, so that the calculation precision is fully improved; and finally solving is performed, and a calculation result is obtained according to a stop criterion. According to the method, a coordinate transformation process and a measurement point preprocessing process in geometry are not calculated; the measured data can be fully applied; the method is relatively novel in algorithm application; a test function is more accurate in comparison with other common algorithms; the iterative speed is higher; and the solving process completely conforms to a minimum area principle in international standards, so that the calculation result is higher in precision.