The invention discloses a measurement method of concrete resistivity and a device thereof. The measurement method comprises the following steps: a. arranging an electrode respectively at two ends of the concrete to be detected; b. applying direct current of a steady state value between the above two electrodes, measuring the electric potential between the electrodes and recording as energization electric potential; c. disconnecting the direct current applied on the electrodes, measuring the electric potential between electrodes in short enough time and recording as interruption electric potential; d. changing the value of the applied direct current value of a steady state value, repeating the steps of b and c for 0 to 50 times; and e. calculating the concrete resistivity according to the energization electric potential and the interruption electric potential measured in the above steps. The measurement method and device can directly measure the concrete resistivity without destroying the surface structure of the concrete to be detected, the measuring result is stable, the measurement method is rapid and accurate and the measuring instrument is easy to operate.