Abstract: To address the fibrous and flake-like morphology and broad particle-size distribution of calcined needle coke after roller milling, a two-step composite process combining roller milling and spheroidization was proposed. The spheroidization parameters were optimized by orthogonal experiments: the optimum parameters were a main shaft speed of 1500 r·min-1, a classifier speed of 2500 r·min-1, a fan speed of 3000 r·min-1, and a feed speed of 50 r·min-1, with the main shaft speed having the most significant effect. After three spheroidization cycles, the powder showed the best overall performance, with a K-value of 1.25, a tap density of 0.87 g·cm-3, a specific surface area of 1.74 m2·g-1, and an aspect ratio of 1.20. After graphitization, the initial coulombic efficiency was 94.93 % and the internal resistance was 35.64 mΩ; the capacity retention was 89.5 % at 2 C and 94.6 % after 500 cycles at 0.5 C. Moderate spheroidization enhances particle collision, friction, and shear, whereas excessive spheroidization shifts the dominant mechanism from surface grinding to bulk fragmentation, increasing fines and deteriorating powder properties. The two-step process improves the properties of needle coke powder and provides a reference for the large-scale preparation of artificial graphite anodes.