Abstract: Carbon fiber reinforced thermoplastic resin matrix composites (CFRTP) are sensitive to temperature change. A composite heat source model for the peripheral milling process of carbon fiber (CF)/poly(ether-ether-ketone) (PEEK) thermoplastic composites was established, which included the plastic deformation of anisotropic materials and the multi-faceted friction from tool-workpiece and tool-chip. The cutting heat distribution ratio of tool-chip-workpiece was solved when cutting thermoplastic composites in different fiber orientations. Finally, a prediction model for the peripheral milling temperature of thermoplastic composite materials was constructed, and the effects of process parameters such as fiber orientations, cutting speed and feed rate were analyzed. Through experimental verification, the average prediction error of the model is less than 11.5%. The results show that a higher proportion of heat flows into the workpiece when performing machining with a large cutting angle, resulting in higher milling temperatures. With the increase of cutting speed, the milling temperature first increases and then decreases, and the critical value is around 100 m/min. As the feed rate increases, the overall milling temperature shows a downward trend. When the feed rate increases from 0.01 to 0.1 mm/r, the milling temperature decreases by more than 40%.