Finite-size behavior near the critical point of QCD phase-transition

It is pointed out that finite-size effect is not negligible in locating critical point of QCD phase transition at current relativistic heavy ion collisions. Finite-size behavior near critical point, in particular, finite-size scaling and fixed-point behavior of the final observables can be served as a quantitative identification of critical point and the nearby boundary of the QCD phase transition. The validity of the method at finite detector acceptances at RHIC is discussed.