The invention provides a determination method and device of power data sampling precision in the energy internet. The method comprises the steps that a power data sample set F is built; according to the power data sample set F, a power data phasor matrix D is built, and filling treatment is conducted on the power data phasor matrix D; according to a power data phasor matrix D' after the filling treatment, a correlation coefficient matrix r and an index parameter are determined; according to the index parameter, a multi-factor quantitative model is built, and thus the sampling precision of the power data is determined. By means of the determination method and device of the power data sampling precision in the energy internet, a data processing load in the same period can be relieved, sampling precision is scientifically selected to record an output track of an intermittent power supply, true reappearance of a system operation track is carried out, the method and device are beneficial to reduction of the power data storage cost in a large wind farm or a photovoltaic power station, and management difficulty is reduced.