In this paper, we investigate additive properties of generalized Drazin inverse for bounded linear operators. As an application we present new conditions under which a 2 × 2 operator matrix has g-Drazin inverse. These extend the main results of Dana and Yousefi (Int. J. Appl. Comput. Math., 4(2018), page 9), Yang and Liu (J. Comput. Appl. Math., 235(2011), 1412–1417) and Sun et al. (Filomat, 30(2016), 3377–3388).