With the development of power system visualization，the voltage contour bitmap has become an effective means of observing the reactive power and the voltage limits of the grid.The advantages and disadvantages of typical interpolation algorithms available for the voltage contour bitmap are generalized.On the basis of a large amount of practical work，the logarithmic distance inverse weighting method is proposed.Simple in calculation，this method does not require the complex solving process as in Kriging interpolation，greatly saving computation time and improving computational efficiency.Moreover，much better display effect is achieved than the distance inverse method.Application in practice shows that the voltage contour bitmap obtained is able to make more vivid and intuitive description of the regional voltage trends with more natural color transition.