Provided is a reagent for acridinium ester chemiluminescence, including a graphene-based material; hydrogen peroxide; and an acid, and a reagent system including the same, and a method of detecting a target antigen in a sample, including: performing immunoreaction between a target antigen in a sample with a detection antibody or an artificial antigen consistent with the target antigen conjugated with acridinium ester to form an acridinium ester-labeled immunocomplex; dispersing the acridinium ester-labeled immunocomplex in a first reagent comprising an acid, hydrogen peroxide and a graphene-based material; adding a second reagent including a base and a surfactant into the dispersed acridinium ester-labeled immunocomplex to emit chemiluminescence signal; and measuring an intensity of the chemiluminescence signal.