According to an arctic-physic model of unified interactions,as well as the relationship between gravitational potential and electrostatic potential,from definitions of the field strength,potential energy,force and potential in classical physics,the relationship between gravitational field strength and electrostatic field intensity was concluded,in which the relations between the field strength and the potential in classical physics was used.The relationship between gravitational potential energy and electrostatic potential energy was concluded,and also the relationship between gravitational force and electrostatic force was concluded,in which the relations between the potential energy(and force) and the potential in classical physics was used.On that basis,the definitions of the intensive electrostatic potential and the intensive electrostatic potential energy and intensive electrostatic force of system were proposed.The nuclear intensive electrostatic potential on atomic boundary(V_ic) was discussed.It reflected the capacity that the dynamic nucleus attracted and droved outermost electron on atomic boundary.V_ic of 95 nuclei were calculated by the essential parameters(nuclear mass,quantity of electricity and atomic radius).A set of nuclear V_ic was obtained.The periodicity gradation of V_ic in periodic table reflected systematically the periodicity gradation of atomic structure.It mainly decided the elemental properties and the periodicity gradation in periodic table.