System doors pursue excellence in craftsmanship. Whether in scorching summer or cold winter, they can effectively block heat transfer, maintain a comfortable indoor temperature, reduce energy consumption, and practice the concept of green environmental protection. Automotive-grade EPDM sealing strips, combined with a unique multi-channel sealing structure such as four or five sealing processes, create a high-strength sealing effect, which can effectively block the intrusion of wind, rain, and dust, ensuring a clean and dry indoor environment. The frame and sash assembly adopts reinforced integrated corner code connection, which has high structural strength, making the frame and sash assembly firm and stable. The screw holes of the sash corner codes are hidden, which not only enhances the appearance but also improves the overall safety. In addition, the door frame and threshold adopt design to further enhance the sealing performance; the indoor side adopts a beveled anti-kick design, which is considerate and safe; the triangular design of the indoor threshold can better resist impact in unconventional door-closing situations, such as windy days or slamming the door, ensuring the sealing performance of the door leaf and threshold.