Spatial correlation is one of the main factors restricting performance of the wireless optical communication (WOC) multipleinput multipleoutput (MIMO) system. The channel model of correlated WOC MIMO systems combined with OOK modulation technology is established. Then, the expressions of average channel capacity of WOC MIMO system for different correlated mechanisms are derived and the outage performance is analyzed. Finally, the impacts of spatial correlation on average channel capacity and outage channel capacity of WOC uniform circular array MIMO system in lognormal fading channel are simulated. The results show that spatial correlation deteriorates the average channel capacity of WOC MIMO system and increasing the probability of interruption. Meanwhile, the impacts of complete correlation are more serious than that of partial correlation on the performance of WOC MIMO system.