Let Fq be a finite field of any characteristic and GL(n,Fq) be the general linear group over Fq.Suppose W denotes the standard representation of GL(n,Fq),and GL(n,Fq) acts diagonally on the direct sum of W and its dual space W*.Let G be any subgroup of GL(n,Fq).Suppose the invariant field Fq (W)G =Fq (f1,f2,...,fk),where f1,f2,...,fk in Fq[W]G are homogeneous invariant polynomials.We prove that there exist homogeneous polynomials l1,l2,...,ln in the invariant ring Fq[W ⊕ W*]G such that the invariant field Fq(W ⊕ W*)G is generated by {f1,f2,...fk,l1,l2,...,ln} over Fq.