Based on the analytical expression of the static voltage stability limit derived from apparent power, this paper gives an index to identify the weak point of static voltage stability, and proposes an improved engineering calculation method for the static voltage stability limit. The power system simulation software is mainly used in the project to calculate the static voltage stability. This method simulates the load growth in the stability calculation program, and solves the problem of limit misjudgment caused by the difficulty of the convergence of the operating point near the static voltage stability limit in the ordinary power flow algorithm. In the power flow calculation program, the PV node of the generator in the region is modified to a PQ node, which solves the problem of excessive output of reactive power caused by the dynamic calculation characteristic of the generator in the stable calculation program. Finally, a certain district power grid in Beijing is used as an example to verify the adaptability of the calculation method.