Abstract: Provided are a human LIFR antigen binding protein, a preparation method therefor, and an application thereof. A series of human LIFR antibodies having biological functions are obtained using human LIFR-ECD protein immune H2L2 humanized antibody transgenic mice by means of single B cell cloning technology (SBC), single B cell sequencing analysis, and Fc recombination. The method greatly improves the discovery efficiency and the yield of antibody drugs, and the obtained human LIFR antibody has good affinity and can block the binding of huLIF proteins to huLIFR/gp130 cells, thereby inhibiting signaling pathways such as STAT3, further inhibiting the growth of tumors, and achieving the purpose of tumor prevention and treatment.