Quantum affine algebras are quantum enveloping algebras of affine Lie algebras, introduced independently by Drinfeld and Jimbo in their study of the Yang-Baxter equation. Representation theory of quantum affine algebras depend mostly on the Drinfeld realization. Quantum toroidal algebras and Quantum extended affine algebras are quantization of toroidal Lie algebras and extended affine algebras respectively. We will discuss our recent joint work with F. Chen, F. Kong and S. Tan on Drinfeld realization for twisted quantum extended affine algebras, in particular we will study deformation of all nulity two quantum extended affine algebras.