Abstract: In this study,the effects of five parameters including the pipe radius,the borehole radius,the pipe-pipe distance,soil thermal conductivity and grout thermal conductivity on the value of borehole thermal resistance are investigated. A 2D heat conduction numerical model is established using Comsol finite element software and its accuracy is verified. In order to implement the analysis,L²⁷（3~5）orthogonal array is established and the values of borehole thermal resistance in different parameter combination are obtained. The optimal parameter set are attained by applying the Taguchi method. The optimal parameters combination is shown as follows:r_p= 0.020 m,r_b= 0.06 m,x_c= 0.07 m,λ_s= 0.90 W/（m·K）,λ_g= 2.00 W/（m·K）. Results using above optimal parameter set reveals 81.67% decrement in the borehole thermal resistance and 35.79% decrement in the borehole length. The analysis of variance technique is carried out lastly to figure out the relative importance of tested parameters. The pipe radius,grout thermal conductivity and borehole radius play vital roles in optimizing the value of borehole thermal resistance whereas the pipe-pipe distance and soil thermal conductivity’s impact can be nearly neglected.