The present invention relates to a long-acting human follicle-stimulating hormone formulation having improved in vivo duration and stability, comprising a human follicle-stimulating hormone conjugate that is prepared by covalently linking human follicle-stimulating hormone with an immunoglobulin Fc region via a non-peptidyl polymer, and a preparation method thereof. The long-acting human follicle-stimulating hormone formulation of the present invention maintains in vivo activity of human follicle-stimulating hormone at a relatively high level and remarkably increases the serum half-life thereof.