Expression of ahigh concentration of H 2 Sisclosely related to the formation of colon cancer tumors.However,only af ew H 2 S-triggered theranostics agents for colon cancer have been reported to date.N ow,at urn-on theranostics agent was developed by utilizing the in situ reaction of Cu 2 Oa nd endogenous H 2 Sa tc olon tumor sites.B ased on in vitro and in vivo experiments,e xcellent photoacoustic imaging and photothermal therapyw ere both confirmed by this in situ reaction-activated colon cancer theranostics method. This work established as imple and efficient strategy for both diagnosis and treatment of colon cancer with an ovel trigger mechanism, whichp rovides an ew route for colon cancer theranostics based on the in situ reactions at the tumor sites.