Given a finite-dimensional algebra
A over a field
k, and a quiver with relations (
Q,I), let Λ =
A⊕
kkQ/I. The category Λ-Mod (Resp. Λ-mod) of (Resp. finitely generated) Λ-modules is equivalent to the category Rep(
Q, I,A) (Resp. rep(
Q, I,A)) of (Resp. finite-dimensional) representations of (
Q, I) over A. The main result of this paper explicitly describes the Gorenstein-projective modules in rep(
A3,I,
A), where (
A3, I) = 3
α 2
1. with relation I = < β
α >. As a corollary, we give a necessary and sufficient condition for A being a self-injective algebra.