Cryptosporidiosis, a protozoan disease, is caused by Cryptosporidium parvum in animals and humans. To study the humoral and cellular immune responses induced by DNA vaccine expressing the sporozoite surface protein, CP15/60, of Cryptosporidium parvum, the recombinant plasmid containing the CP15/60 gene was injected into tibialis a interior muscle of BALB/c mice. The mice were subsequently given booster doses twice at 3-week intervals. The humoral and cellular immune responses were detected at different times after immunization. The mice were then challenged by inoculation of 1 × 10⁶ oocysts of C. parvum. The experimental results have shown that the recombinant plasmid can induce corresponding specific immune responses and thus protect the mice from challenge of the oocysts, suggesting that the recombinant plasmid could be a potential candidate of DNA vaccine.