Abstract: Translocation and accumulation of organic substance in Xanthoceras sorbifolia Bunge, an oil tree species widely distributed in North China, have been studied by ringing method and 32P tracer technique. It was found that the organic nutrients for the growth of new shoots, new leaves, flowers and fruitlets all came from the reserves in branches, trunk and root system in the previous year. Foods synthesized in the newly formed mature leaves were translocated partly to fruits and apical bud of the same branch and partly to other branch, trunk and root system. Translocation of foods synthesized in the leaves to the growing fruits stopped about half a month before fruit maturation, they were translocat to other branches, trunk, root system and buds instead. This was apparently necessary for the growth and differentiation of flowers and fruits next year.