The present disclosure provides a nuclear detection simulation device based on a nanosecond light source and a nuclear signal inversion technology. Electronic circuits and nuclear pulse current signals are used to drive blue LEDs to emit nuclear pulse optical signals, so as to simulate a scintillator to receive γ radiation to emit light, and can simulate point sources and area sources, organic scintillator detectors and inorganic scintillators, scintillation efficiency and detection efficiency, radioactive sources, fast components and slow components, multi-type nuclear pulse signals, a statistical fluctuation phenomenon of nuclear pulses, the electron pair effect, the Compton effect, the photoelectric effect, and self-radiation of the scintillator, generate single or piled-up pulse signals, corresponding energy spectrum curves, and an environmental background spectral line. 3D visualization configuration and a nuclear signal detection process can be subjected to animated demonstration.