Abstract: This study used delayed matching task. Slow cortical potentials were measured when 16 normal participants were performing object and spatial working memory task. The results were as follows: at global posterior brain regions, dissociation in time of slow cortical potentials between object and spatial working memory task was found, and excessive posterior brain regions were activated in spatial working memory task. Left inferoprefrontal cortex（LIPFC） was activated in object and spatial working memory task, and there was not significant difference in intensity of activation. The dorsolateral prefrontal cortex（LDPFC） was responsible for maintenance and rehearsal of object information，but there was not symmetrical in intensity of activation between left and right dorsolateral prefrontal cortex.

Key words: object working memory, spatial working memory, slow cortical potentials, dissociation