Abstract: G protein-coupled receptors (GPCR) are the most studied drug targets, responding to over 30% of modern marketed drugs. The molecular structures and functions of this large family of transmembrane proteins have been the subject of heavy research by both the pharmaceutical industry and academia. Recent breakthroughs in GPCR crystallography have led to high-resolution structures of over 30 class A GPCR, which have provided the structural basis for rational drug design and functional studies, unveiling new drug targets and ligand design strategies. The structures also have been widely applied to computational approaches in GPCR research. A few groundbreaking studies in the last few years have significantly advanced the understanding in GPCR structures, dynamics, activation and ligand recognition. This mini-review summarizes the recent updates on class A GPCR structure and function, with a focus on the applications and perspectives of molecular modeling in GPCR ligand design.