A timing apparatus and method for a radiation detection, measurement, identification, and imaging system are disclosed. The apparatus comprises high-energy photon detectors, a light pulse signal generator and an optical fiber. Each high-energy photon detector comprises a scintillation crystal and an optical-to-electrical conversion multiplying device. The high-energy photon detectors are all provided with light transmission holes. Light pulse signals are propagated to the scintillation crystals through the light transmission holes, then propagated to the surfaces of the optical-to-electrical conversion multiplying devices through the scintillation crystals, converted and multiplied by the optical-to-electrical conversion multiplying devices, and processed and read by an electronic circuit. The high-energy photon detectors independent from each other acquire absolute time from the light pulse signals generated by the light pulse generator and timing and calibration are performed between the independent high-energy photon detectors.