Abstract: With urea as the precursor, bulk g-C₃N₄was thermal polymerized at 550℃ for 5 h.The g-C₃N₄nanosheets were prepared by exfoliation of g-C₃N₄bulk via ultrasound.Then CdS in-situ growing on g-C₃N₄nanosheets was realized by hydrothermal method.g-C₃N₄-CdS heterojunctions exhibit a broad photoabsorption at about 525 nm, revealing an obvious red-shift compared with g-C₃N₄ (about 460 nm).Furthermore, g-C₃N₄-CdS heterojunctions can degrade 99% of rhodamine B and possesses high photocatalytic activity.