Two alternate arguments in the framework of intrinsic metrics and measures respectively of part of the proof of a famous theorem due to Qi-Keng Lu on Bergman metric with constant negative holomorphic sectional curvature are presented. A relationship between the Lu constant and the holomorphic sectional curvature of the Bergman metric is given. Some recent progress of the Yau's porblem on the characterization of domain of holomorphy on which the Bergman metric is Kähler-Einstein is described.