The effects of ethephon on ripening and increasing sucrose content in mature and immature intemodes of sugarcane (Saccharum spp. hybrid) were studied with three varieties, namely, early-maturing variety ROC16, GT11 and intermediate variety GT15. The results showed that the effects of ethephon were varied from different varieties and (or) internodes. Ethephon significantly increased the sucrose contents in cane of immature internodes, but not in those of mature variety and (or) mature internodes. Ethephon significantly decreased the reducing sugar content in juice of mature and immature intemodes for all the three varieties, but the effect on immature intemodes was more significant than that on mature intermodes. The effect of ethephon on the juice gravity purity depended on the mature degree of the varieties and (or) intemedes, and greater effect on the juice gravity purity was shown in the less maturing ones. All these effects lasted for the whole experimental period (10 weeks) while the sugarcane growth was not retarded.