Abstract:The pinnae of compound leaf of Cycas could produce and evolve from a single pinnae to dichotomous pinnae gradually. From the first dichotomous, the pinnae will grow up and develop bi_,tri_even to multidichotomously usually in different species or sometimes in the same species. The species of the last form could be one of the most advanced species of Cycas. Stangerioides with forked pinnae should be the most advanced species of Cycas.