The invention discloses a double-voltage-regulating power source for extra-high voltage current transformer verification. The power source is composed of a main voltage regulating unit and a micro voltage regulating unit in series connection. The main voltage regulating unit is composed of a main voltage regulator and achieves a wide-scope adjustable voltage source with a voltage of 0-800V and with an adjustment fineness of 1V. The micro voltage regulating unit is composed of an auxiliary voltage regulator and an isolation step-down transformer with a transformation ratio of 20/1, and achieves a fineness adjustable voltage source with a voltage of 0-20V and with an adjustment fineness of 0.05V. Verification of two verification points of 1% and 5% conveniently can be achieved. The double-voltage-regulating power source ensures accurate regulating of a small current, and can find verification points of 20%, 100% and 120% accurately and rapidly. The double-voltage-regulating power source has characteristics of rapid regulating speed, wide voltage regulating scope and small regulating fineness, is stable and reliable, and is suitable for usage of extra-high voltage current transformer verification.