RF Level Controller uses of high frequency technology to generate lower power RF signal by electronic circuit on the probe, which feeds back signal changes from dielectric constant of level to circuit as a sensing element; For these changes include the change of electric capacity and conduction, so what circuit processing are complex change signals of capacity reactance and impedance; The phase testing technology will examine the changes out and alter the output state of relay after processing. It is improved to be the RF measuring technology as the base of original capacitor and presents a new level of level measuring nowadays.