High sugar character is one of the important assessment indexes for selecting and breeding excellent sugarcane varieties. In order to screen important proteins that may be involved in sugar synthesis and accumulation during the ripening process of different sugarcane varieties, and to provide theoretical basis for future breeding of sugarcane varieties with high sugar maturity, the early-maturing sugarcane variety GL05-136 and late-maturing sugarcane variety GR2 were used as experimental materials. iTRAQ technique was used to identify the intraspecific and interspecific proteomic differences between the two sugarcane varieties at different sampling periods.