The traditional flood cooling method applied in the internal turning process has disadvantages, such as having a low cooling efficiency and being environmentally unfriendly. In the present work, an internal spray cooling turning tool was designed, and the performance was numerically and experimentally accessed. The heat transfer simulation model of the internal spray cooling turning tool was established by ANSYS Fluent, and the tool cooling structure parameters were optimized by the Taguchi method based on the CFD simulations, and obtains the diameters of the upper and lower nozzles of 3 mm and 1.5 mm, respectively; the distance between the upper nozzle and the tool tip of 18.5 mm. To evaluate the cutting and cooling performance of the optimized tool, internal turning experiments were conducted on QT500-7 workpieces. Results show that the optimized tool with internal spray cooling led to lower workpiece surface roughness and chip curling, compared to the conventional tools.