The invention relates to a humanized anti-human PD-L1 monoclonal antibody, preparation method and use thereof. The humanized anti-human PD-L1 monoclonal antibody provided by the present invention has high affinity and high specificity to PD-L1, can stimulate T cells to secrete cytokines, and specifically abolish the immunoregulatory effect of PD-L1, and such function is not achieved by directly blocking the interaction of PD-1 with PD-L1, presenting a new regulatory mechanism for immune checkpoint activity. Thus, the functional humanized anti-human PD-L1 monoclonal antibody provided by the present invention can activate T cells by regulating the PD-L1 signaling pathway, thereby achieving the purpose of tumor immunotherapy.本發明涉及一種人源化抗人PD-L1單克隆抗體及其製備方法和用途。本發明提供的人源化抗人PD-L1單克隆抗體對PD-L1具有高親和性、高特異性，能夠刺激T細胞分泌細胞因子，特異地解除PD-L1的免疫負調節作用，並且這種抗體的作用不是通過直接阻斷PD-1與PD-L1相互作用實現的，呈現了新的免疫檢查點活性調節機制。因而，本發明提供的功能性人源化抗人PD-L1單克隆抗體，可通過調節PD-L1信號通路來激活T細胞，進而實現腫瘤免疫治療的目的。
