Provided are an immune effector cell expressing a chimeric protein and an application thereof. The immune effector cell expresses a chimeric protein containing an extracellular domain of a TGF-β receptor and an intracellular signal domain of a receptor of an IL-2 family protein. Further provided are a pharmaceutical composition containing the immune effector cell and a use of the immune effector cell or the pharmaceutical composition for the preparation of a medicament for preventing or treating tumors or pathogenic microorganism infection. The immune effector cell expressing the chimeric protein of the present invention is capable of transforming stimulation of TGF-β into a positive signal of IL-2, IL-7, or IL-21, and inhibiting TGF-β-induced Treg differentiation, thereby promoting survival and proliferation of immune cells, and is also capable of reducing the effect of TGF-β on cell killing ability.