Abstract: A new and advanced DirectShow technology for multimedia application development is presented. This technology is applied in a networked digital video monitoring system based on MPEG-4. Multimedia processing is realized in DirectShow frame,including capturing, decoding, playing back, seeking etc. This technology not only makes it simple to develop multimedia programme, but also satisfies real-time feature and adjustable definition of monitoring system. This paper offers a whole solution for application of MPEG-4,which is not standardized at present.