There is no long-distance 500KV voltage cable operating experience home, in order to better study long-distance 500kV oil-filled undersea cables running electrical performance, this article take measures of the rated current load based on the DC voltage to verify the cable insulation level. As the electric field and charge distribution plays a decisive role in insulating level of the insulating layer, but the process of load voltage and current increasing leads to the internal temperature conductivity and other parameters dynamically changing in the cable, which leads to the electric field and the charge making corresponding changes. This paper in process of loading voltage and charging analyses the electric field distribution characteristics inside the cable and influencing factors, the rapid calculation of charge etc, besides cable deducing theory of cable to build the establishment of dynamic calculation model of charge and electric field. Calculate charge distribution of the electric field by numerical simulation software to verify the accuracy of the calculation model and improve the calculation model. The establishment of the model remainder of the charge, as well as of to provide the corresponding theory for the calculation of electric field and charge in the practical operation.