Abstract: Concealed mark preparation with core-shell luminosphores for customs security check system and application thereof, to address that infrared luminescent materials have not been used in senseless customs clearance field, absorption cross sections of infrared luminescent materials currently available are not big enough, and upconversion luminescence intensity thereof is low, consequently, the luminescent marks are not clear enough to recognize marked abnormal luggage, and provide a following solution: step 1: preparing TiQ2; step 2: preparing Ag@TiO2 composite nanoparticles; step 3: preparing Ag@TiQ2@NaYF4:Yb3+, Er3+ luminescent nanoparticles; step 4: making concealed luggage marks.