Zhao and Xu (2013) constructed a functor from \(\mathfrak{o}(n)\) -Mod to \(\mathfrak{o}(n+2)\) -Mod. In this paper, we use the functor successively to obtain full conformal oscillator representation of \(\mathfrak{o}(2n+2)\) in n(n + 1) variables and determine the corresponding finite-dimensional irreducible module explicitly when the highest weight is dominant integral. We also find an equation of counting the dimension of an irreducible \(\mathfrak{o}(2n+2)\) -module in terms of certain alternating sum of the dimensions of irreducible \(\mathfrak{o}(2n)\) -modules, which leads to new combinatorial identities of classical type in the case of the Steinberg modules. One can use the results to study tensor decomposition of finite-dimensional irreducible modules by solving certain first-order linear partial differential equations, and thereby obtain the corresponding physically interested Clebsch–Gordan coefficients and exact solutions of Knizhnik–Zamolodchikov equation in WZW model of conformal field theory.