The invention provides a stand-off ratio voltage coefficient detection method based on a separable direct current voltage divider. The method comprises the steps of 1, measuring the relative error of the voltage of a low-voltage arm resistor of a direct current voltage divider to be measured with a first auxiliary voltage divider as the reference standard; 2, measuring the relative error of the voltage of the low-voltage arm resistor of the direct current voltage divider to be measured with a second auxiliary voltage divider as the reference standard; 3, measuring the relative error of the voltage of the low-voltage arm resistor of the direct current voltage divider to be measured with a voltage divider subcircuit formed by series connection of the first auxiliary voltage divider and the second auxiliary voltage divider as the reference standard; 4, calculating the stand-off ratio voltage coefficient of the direct current voltage divider to be measured. Compared with the prior art, the method has the advantages that detection is easier and more convenient, a detection result is more accurate, and the influence of the difference in low-voltage arm resistors of auxiliary voltage dividers on calculation of the stand-off ratio voltage coefficient of the direct current voltage divider to be measured existing during a direct voltage addition test is avoided.