Objective To optimize the parameters for the synthesis process of polycrystalline diamond ( PDC) films. Methods Using the holding time, cooling time and sintering temperature as variables, orthogonal experiments were designed for the synthesis of PDC) film. The side-assembling block was used for thermal sintering, the hardness, wear ratio and the resistance value were measured for the sintered finished PDC, and the amounts of intact products were determined for each group of sintered products, and the orthogonal experimental results were analyzed by the overall balance method. Results Holding time, cooling time and sintering temperature affected the overall quality of PDC to varying degrees. Conclusion The optimal parameters were: synthesis temperature 1350 ℃ , heating time 5 min, cooling time 11 min.