It is important to regulate the concentration of reactive oxygen species (ROS) in cells since they play important roles in metabolism.Thus,developing nanoreagents to control the ROS is critical.Herein,tellurium-doped carbon quantum dots (Te-CDs) were developed by a simple and efficient hydrothermal method,which can scavenge H2O2 to protect cells under ambient condition,but generate.OH under 808 nm irradiation as photodynamic application.This contribution presented a kind of novel CDs with dual-functions,which can potentially regulate ROS under different conditions.