With the continuous development of multimedia communication technology, it puts forward higher requirements for real-time and low-latency communication systems. This paper proposes a design and optimization method for low-latency realtime communication systems based on multimedia transmission. First, the basic requirements of real-time communication systems are analyzed, and then multimedia transmission protocols and technologies, codec technologies and compression algorithms, network topology and transmission path optimization are introduced. Then, the design principles of low-latency realtime communication systems are discussed, including system architecture and design elements, real-time transmission protocol design, codec optimization and implementation, system scheduling and management strategies, etc. Finally, the system is optimized and performance improved, including system performance analysis and optimization requirements, system resource management and tuning, network topology optimization and path selection, etc.