In order to overcome defects of a stabilized-current power supply used for ground resistivity measurement in industries such as earthquake observation, earthquake engineering and hydrogeology currently, meet the technical requirement that ground resistivity observation is anti-interference and realize needs of AC/DC comparative observation and joint observation, the invention provides an uninterrupted variable-frequency stabilized-current power supply which is designed by using a switching power supply technology and a variable-frequency inverter technology. According to the power supply, sine-wave low-frequency AC stabilized-current power with frequency and current programmable can be outputted for being used by a ground resistivity observation device, or DC stabilized-current power with current programmable can be outputted for being used by the ground resistivity observation device, and 220V/50Hz AC can be outputted for being used by other power consumption devices. The uninterrupted variable-frequency stabilized-current power supply is mainly composed of a switching stabilized-voltage power circuit, a charging circuit, a variable-frequency stabilized-current inverter circuit, a 220V/50Hz AC inverter circuit, an AC/DC reference signal generation and control circuit, a battery pack and a working power circuit.