The model of a three-terminal thermoelectric refrigerator with ideal tunneling quantum dots is established.It consists of a cavity connected to two quantum dots embedded between two electron reservoirs at different temperatures and chemical potentials.According to the Landauer formula the expressions for the heat current,the cooling rate and the coeffcient of performance (COP) are derived analytically.The performance characteristic curves of the cooling rate versus the coefficient of performance are plotted with numerical calculation.The optimal regions of the cooling rate and the COP are determined.Moreover,we optimize the cooling rate and the COP with respect to the position of energy level of the right quantum dot,respectively.The influence of the width of energy level and the temperature ratio on performance of the three-terminal thermoelectric refrigerator is analyzed.Lastly,when the width of energy level is small enough,the optimal performance of the refrigerator is discussed in detail.