In this paper,spinor and vector decompositions of SU(2)gauge potential are presented and their equivalenceis constructed using a simply proposal.We also obtain the action of Faddeev nonlinear O(3)sigma model from the SU(2)massive gauge field theory,which is proposed according to the gauge invariant principle.At last,the knot structurcin SU(2)Chern-Simons filed theory is discussed in terms of the φ-mapping topological current theory.The topologicalcharge of the knot is characterized by the Hopf indices and the Brouwer degrees of φ-mapping.