The transition points of lattice quantum chromodynamics（QCD） with two degenerate flavors of Wilson quarks at finite temperature T and small imaginary quark chemical potential μ are determined by using the reweighting technique.Under the positive fermion determinant,i.e.,the chemical potential is pure imaginary,the simulations are performed at hopping parameter κ = 0.165.The comparison between the reweighting technique and the conventional point-by-point scanning method is presented.The results prove that the reweighting technique is an effective and efficient method in investigating the critical phenomenon.