In the era of the rapidly developing network, both computer and network technology attain a swift and violent development, and has been well popularized and applied. Under such a background, network security is increasingly focused by more and more people, and all kinds of ways are being sought by people to solve the network security problems. Firewall technology, as a technology to effectively guarantee network security, is also an internal network security and external network defense technology to isolate the internal security, and has been now an important part of network security agencies. In this paper, firewall technology and parts of firewall products are studied to find some problems and some unique ideas are accordingly proposed, and finally the methods for changing the shortcomings of firewall against invasion. Hopefully, the firewall technology can better develop and also better protect the network security in futures.