The invention relates to the field of radiation measurement and provides an on-line type energy spectrum analysis anti-coincidence measurement detector. The detector comprises a sodium iodide scintillator for recording a gamma ray, a photomultiplier for converting an optical signal of the sodium iodide scintillator into a weak pulse signal, a plastic scintillator for deducting Compton flashing of the sodium iodide scintillator, a silicon photomultiplier for converting an optical signal of the plastic scintillator into a weak pulse signal, a lead shielding body for shielding an environment radiation band alignment hole and a lead plug, and a forward amplifying plate for amplifying the weak signals. The detector can achieve complex environment, Compton flashing and serious background interference always on-line measuring, eliminate the influence of nuclear site Compton flashing on 50keV-1.5MeV middle and low energy section radionuclide analysis measurement, and, at the same time, solve the difficulty that anti-coincidence measurement is unlikely to be achieved on a nuclear site.