Litchi trees (Litchi chinensis cv. nuomoci) were sprayed with 0.5mg/l (T1), 0.75mg/l (T2), 1.0mg/l (T3) of brassinolide and withwater (CK) as the control group before anthesis. The enzyme activities of pectin methyesterase (PME), polygalacturonase (PG), cellulase (CX) and the content of water-soluble pectin, protopectin and calcium in the fruit pericarp were studied in order to investigate the effect of brassinolide on litchi pericarp during its development. Content of water-soluble pectin remained at a higher concentration during early stages of development of treated fruit compared to control fruit. Protopectin content increased during fruit development and reached a peak after 58 days of anthesis. PME and PG activities both increased and showed the same trend under T1, T2 and T3 as the concentrations of pectin and protopectin. Calcium concentration of fruit pericarp was higher in treated fruit than control fruit and showed significant dosage response. CX activity was inhibited by brassinolide treatment. The brassinolide reduced fruit cracking compared to the control. The results showed that brassinolide sprayed before anthesis may play an important role in increasing the commercial value of litchi fruits.