At present, when planning the expansion of power grids, the range of zero-sequence parameter of the new planning equipment is relatively wide and lacks references, which affects the credibility of the result of single-phase short-circuit current. Thus, a zero-order parameter selection method based on the PSD-BPA platform for power grid expansion planning is proposed. Taking each partition of a local power grid as a typical scenario, the influence of the changes of zero sequence parameter XO card of 500 kV main transformer, zero sequence parameter LO card of 220 kV line, and sub equivalent zero sequence parameter XR card value of high-voltage side bus of 220 kV main transformer on single-phase short-circuit current of 220 kV side bus in that scenario of the BPA transient stability are analyzed. The key influencing factors are identified through error analysis, then according to the requirements of the calculation error, give advices to zero sequence of accessor according to the included important factors. An example analysis shows that the proposed method can easily and effectively evaluate the single-phase short-circuit current of bus at 220 kV side of Shanghai power grid 500 kV substation in the planning year, and can be applied to engineering practice.