From φ-mapping method we construct a fourth-order topological tensor current in general. It is shown that the inner structure of this topological tensor current is labelled by the δ-function δ(φ), which represents some four-dimensional singular manifolds. By investigating the total expansion of δ(φ), these singular manifolds carry the topological numbers β i η i naturally, which does not involve any concrete models. As the generalization of Nielsen's Lagrangian and Nambu's action for strings, we present a new coordinate condition in general relativity, which includes the Fock's coordinate condition as a special case.In nonlinear σ-models, 9 the Skyrmions currents 10 (whose charges have many properties in common with baryon numbers 11 ), the topological current of dislocation and disclination continuum, 12 the space-time defects in the early universe, 13 the GaussBonnet-Chern theorem and the topological charge of Chern class. 14 In our previous papers, 2,5,7 based on the so-called φ-mapping method, only topological current of point-like particles was discussed. In this letter we will extend the concept. We consider the φ-mapping as a map of an n-dimensional Riemann manifold X onto an (n − 4)-dimensional Euclidean space R n−4 . From this map we can construct a fourth-order topological tensor current and study its inner structure naturally. From the viewpoint of submanifold of X, four-dimensional Riemann manifolds are generated by the kernel of φ-mapping and the famous Fock's coordinate condition is naturally deduced without any concrete models.We start by introducing the so-called φ-mapping method. Let X be an ndimensional Riemann manifold with metric tensor g µν and local coordinates x µ (µ, ν = 1, . . . , n), and R n−4 a Euclidean space with dimension m = n − 4 and coordinates φ a (a = 1, . . . , m). A smooth map φ: X −→ R n−4 gives an (n − 4)-dimensional smooth vector field on X, which can be represented in the coordinate 745 Mod. Phys. Lett. A 1998.13:745-752. Downloaded from www.worldscientific.com by UNIVERSITY OF CALIFORNIA @ SAN DIEGO on 06/04/15. For personal use only.