In researches of space flight, studies on the effects of microgravity on cognitive function were relatively few. This paper reviews recent progress on this topic. It was shown that under the condition of microgravity, spatial orientation, motion perception and early process of object recognition were impaired to a certain degree. Capability of muscle movement and coordination was lowered, while higher cognitive functions, such as logic reasoning task, the speed and accuracy of short-term memory retrieval were less affected by microgravity. But long-term memory tasks and performance in which attention processes were needed (e.g., tracking task, selective response task), were impaired during space flight or under simulated weightlessness condition.