Abstract: As a core component of the central air conditioning system, the indoor unit's assembly accuracy and production efficiency are the key elements of the production line. Currently, traditional production lines suffer from low levels of intelligence, poor process coordination, and data silos, which urgently require a transformation towards intelligence. Based on this, the design work of the intelligent assembly production line and the spraying system for the central air conditioning indoor unit was carried out. Firstly, the overall production line scheme was designed. Through modular layout design and integration of intelligent monitoring systems, a U-shaped intelligent assembly production line was constructed, integrating eight workstations including the locking of the axial flow fan. Secondly, the hardware system design of key workstations was carried out. Innovative developments included a locking mechanism based on torque-angle compound control, a spraying system with dynamic path planning, and an electrical inspection device for multiple workstations in parallel. Finally, the main production line fixtures and the spraying system were designed, and the process principle of spraying and the influencing factors of spraying effect were analyzed. After the process balance optimization of the constructed intelligent assembly production line, the production efficiency of the production line increased by 86.8%. Through dynamic spraying, the spraying coverage rate increased by 23.6%. This not only realized the continuous and intelligent assembly production line of the central air conditioning indoor unit, but also provided technical support for the discrete intelligent manufacturing in the equipment manufacturing industry.