Disclosed are fully human anti-PD-Ll antibodies and their corresponding applications. Fully human antibodies are capable of specifically binding to human PD-L1. Antibodies were obtained by employing a yeast display library-based screening technique and also by affinity maturation to further improve their affinity for PD-L1. The fully human anti-PD-Ll antibodies disclosed show good specificity, affinity and stability. They are capable of enhancing T cell activity by binding to activated T cells, while significantly inhibiting tumor growth. Disclosed fully human anti-PD-Ll antibodies can be used in the diagnosis and treatment of PD-Ll-related cancers and other associated diseases.