Abstract: A portable radiation detection apparatus is provided to transform detected radioactivity into an analog pulse signal and then convert the analog pulse signal into a digital pulse signal. Thereafter, a counting information with respect to the pulse width and pulse counting of the digital pulse signal is created for data processing executed in a portable device. A spectrometric analysis method is provided, which comprises the steps of generating a smooth and continuous curve with respect to the counting information, searching peak values and channel numbers corresponding to the peak values toward the smooth and continuous curve, calculating FWHM and region of interest of the peak values and then processing counting rate process. According to the foregoing characteristics, the present invention is not only provide lowing cost and wireless communication but also provide distance protection for radiation protection personnel to execute the inspection routinely under the extremely environment.