In order to design a 10 kV high-precision electroscope with contact and non-contact power inspection functions,a new high-voltage power inspection method is proposed. A 10 kV new combined electroscope is developed by using the partial voltage principle of stray capacitance and the charge-sensing principle of the planar capacitive electric field sensor. In this paper, the power frequency electric field distribution is analyzed, the voltage division principle of the spatial stray capacitance and the inductive voltage calculation formula of the electric field sensor are derived. Ansoft Maxwell is used to simulate electromagnetic fields in a variety of electrical environments and analyze the anti-jamming capability. The hardware circuit and software program are designed simultaneously. The contact electricity inspection test and the non-contact electricity inspection test are carried out under the built high-voltage test platform. The results show that under the high-voltage transmission environments, the variation of induced voltage of non-contact electroscope conforms to the variation law of electric field strength, and contact and non-contact electroscope have higher accuracy of electroscope. This work is supported by National Natural Science Foundation of China (No. 51577022).