Abstract: As an important sort of cyberspace security threats, computer viruses have been a hotspot in cyberspace security research. Inspired by the gene theory and the artificial life theory, we present a gene-based model of computer viruses evolution. The form definition of the computer virus is given and the mathematical models of computer viruses evolution in the three levels of gene, DNA, and chromosome are constructed. And then the computer viruses evolution process in natural selection is simulated. Experimental results show that, even in face of harsh external environment, computer viruses which have characteristics of both algorithm and life still have strong ability of adaptation and evolution.