The invention discloses a high-range ray rapid measurement device and a measurement method thereof. The measurement device is provided with a main detector, an operational amplifier unit, an analog-digital conversion unit and a control unit which are sequentially and electrically connected in series. The main detector is provided with a plastic scintillator; the main detector is provided with at least one energy compensating plate clung and fixed to the ray incident end of the plastic scintillator; the energy compensating plate is provided with a base material main body made of an acrylic photoconductive material, and an outer coating formed by spraying zinc sulfide on the outer surface of the base material main body. The high-range ray rapid measurement device disclosed by the invention provides a high-range ray rapid measurement device which can measure various rays and can improve a measurement range and energy response time of low-energy rays of 100keV or lower.