Recently, Gaiotto and Rapcak proposed a generalization of W N algebra by considering the symmetry at the corner of the brane intersection (corner vertex operator algebra). The algebra, denoted as Y L,M,N , is characterized by three non-negative integers L, M, N . It has a manifest triality automorphism which interchanges L, M, N , and can be obtained as a reduction of W 1+∞ algebra with a "pit" in the plane partition representation. Later, Prochazka and Rapcak proposed a representation of Y L,M,N in terms of L + N + M free bosons by a generalization of Miura transformation, where they use the fractional power differential operators.In this paper, we derive a q-deformation of the Miura transformation. It gives a free field representation for q-deformed Y L,M,N , which is obtained as a reduction of the quantum toroidal algebra. We find that the q-deformed version has a "simpler" structure than the original one because of the Miki duality in the quantum toroidal algebra. For instance, one can find a direct correspondence between the operators obtained by the Miura transformation and those of the quantum toroidal algebra. Furthermore, we can show that the both algebras share the same screening operators.