The decay process of photoelectrons of (Zn,Cd)S:Cu,Cl luminescence materials after excitation with short pulse laser was investigated by using microwave absorption dielectric spectrum detection technique. It is shown that with the concentration of CdS increasing,the lifetimes of photoelectrons and shallow-trapped electrons have a descendent trend. Due to the factor that CdS arouses the descend of the conduction band bottom,it changes the forbidden bandwidth of the luminescent crystal and the combination rate of photoelectrons in conductive band and holes in value band increases,the lifetime of photoelectrons and shallow-trapped electrons is shortened. For the shallow traps shackling,the lifetime of shallow-trapped electrons is longer than that of photoelectrons.