Chitinases are important disease-related proteins that play critical roles in plant defense against disease. To investigate the function of chitinases in the resistance of Hami melon to Penicillium infection, the gene encoding chitinases, HmCHT-2, was cloned and RTPCR was used to measure expression levels of HmCHT-2. When the Hami melon was infected by Penicillium sp after 0, 12, 36, 48, 60, and 72 h. The results showed that comparing to the control group, the time of expression levels reaching to the peak delayed and the expression levels maintained at a significantly high level for a longer time. These results suggest that HmCHT-2 may contribute to the defense of Hami melon against fungal infection.