Nowadays, computer network is being universally used in various sectors, which not only brings convenience to these sectors but also changes people's lifestyle. With arrival of the information age, people become increasingly dependent on computer network. Therefore, security of computer network becomes an issue worth of increasing attention. Some advices about how to improve reliability of computer and security of computer network are put forward in this paper. Universal application of computer network represents cultural progress of human society, which brings convenience to people and improves their working efficiency. Degree of people's dependence on computer network has been increasing with improvement of network information technology. Therefore, people have higher requirements on security and anti-interference of computer network. At present, security and anti-interference of computer network are among the most important issues researched by network developers and concerned by a large number of network users. So to speak, reliability of network security has become the most basic requirement of people in using computers, for which how to realize obvious improvement of reliability of computer network and ensure that computers will provide better services to people is of great significance for research.