Abstract: Rubisco activase, a newly found enzyme, could regulate the activity of Rubisco and keep Rubisco in a high activation level under in vivo conditions. It not only had the ability of activating Rubisco but also had the activity of hydrolyzing ATP. The activity of Rubisco was restored by dissociating various sugar phosphates from Rubisco, which required Rubisco activase and ATP hydrolysis. Many perplexing problems of Rubisco activation [WTBX]in vivo had been resolved because of the discovery and studies of Rubisco activase. In this review, the molecular figures and the action mechanism of Rubisco activase, the effects of environmental factors on it were also be introduced.