The present invention relates to a liquid formulation of highly concentrated long-acting human growth hormone conjugate, comprising a pharmaceutically effective amount of the long-acting human growth hormone conjugate in which human growth hormone (hGH) is linked to an immunoglobulin Fc region, and an albumin-free stabilizer, said stabilizer comprising a buffer, a non-ionic surfactant, a sugar alcohol, and sodium chloride as an isotonic agent, and a method for preparing the same.