In order to investigate the changes of defensive enzyme activities in banana infected by Fusarium oxysporum f.sp.cubense race 4 (Foc 4), the activities of phenylalanine ammonialyase (PAL), peroxidase (POD), polyphenol oxidase (PPO), superoxide dismutase (SOD) and catalase (CAT) were determined during the interactions of Fenjiao (ABB) and Brazilian (AAA) banana plantlets with Foc 4 by using artificial inoculation method of dipping injured-roots in conidial suspension. The results showed that the activities of PAL, POD, PPO and SOD were higher in the infected bananas than those in the corresponding non-infected controls, and the changes in activities of PAL, POD, PPO and SOD in infected bananas were more complicated than those in the corresponding non-infected controls, which suggested that these four enzymes actively participated in the resistant response in bananas during the infection of Foc 4. However, the variation trends of CAT activities in both infected and non-infected controls were general similar, indicating that the activity variation of CAT is not related to the infection of Foc 4.