In this paper, we use a geometric technique developed by González-Prieto, Logares, Muñoz, and Newstead to study the G-representation variety of surface groups X G (Σ g ) of arbitrary genus for G being the group of upper triangular matrices of fixed rank. Explicitly, we compute the virtual classes in the Grothendieck ring of varieties of the G-representation variety and the moduli space of G-representations of surface groups for G being the group of complex upper triangular matrices of rank 2, 3, and 4 via constructing a topological quantum field theory. Furthermore, we show that in the case of upper triangular matrices the character map from the moduli space of G-representations to the G-character variety is not an isomorphism.