In the era of "post-PC", embedded system is regarded as a new representation. And its characteristics and developing technology are focused. The traits of embedded system, which are low power processor, compact operating system, prolifically peripheral interfaces and form, and its inner modularized framework are parsed. The typical developing pattern of embedded system is put forward,which is called Host-Target pattern . This pattern can make developers have clear design train of thoughts and divide the work, and also make the developing synchronously. And cross-compile and remote debug is the typical developing characteristics of Host-Target pattern. They are both discussed in this article. Finally we prospect the future of embedded system, and the network, system on chip (SOC) and lower cost of embedded systems are regard as its tendency by author.