Coronaviruses (CoVs) are single-stranded RNA viruses which contain the largest RNA genomes, and SARS-CoV, a newly found group 2 CoV, emerged as infectious disease with high mortality rate. In this study, we compared the synonymous codon usage patterns between the nucleocapsid and spike genes of CoVs, and C-type lectin domain genes of human and mouse on the codon basis using bioinformatics techniques.