Based on Wyner′s wiretap channel,the wiretap channel model of Optica l code division multiple access (OCDMA) systems is established,and “channel ca pacity” and “security leakage factor” are used as indicators to estimate the transmission performance and security of the systems quantificationally.The imp acts of cross-correlation characteristics of address codes on the performances o f OCDMA systems are studied in the paper.Our results indicate that the cross-c o rrelation characteristics of address codes play an important role in the perform ances of OCDMA systems,and using the address codes which have better cross-cor r elation characteristics can improve the transmission performance and security; i ncreasing the code length,using the 2-D address codes or the bipolar address c odes can both improve the transmission performance and security of OCDMA system.