A device for implementing power measurement based on resistance sampling by a linear optocoupler belongs to the electrical measurement field. The device aims at solving the problem of low measurementprecision due to long-distance transmission of measurement results of the existing current dividers/voltage dividers. The device is realized by current signal measurement and voltage signal measurement. An analog current signal acquired by a current divider is converted into a digital signal by a current operation amplification module and a linear optocoupler isolation module, an analog voltage signal acquired by a voltage divider is converted into a digital signal by a voltage operation amplification module and a linear optocoupler separation module, digital signal processing and operation module DSP processing are performed on the obtained two digital signals, polarity of the current signal is judged by a current polarity judgment circuit which transmits identification to the DSP, polarity of the voltage signal is judged by a voltage polarity judgment circuit which transmits identification to the DSP, and the DSP controls a synchronous acquisition voltage signal and a synchronous acquisition current signal. The device is used for field precision power measurement.