The invention provides an automatic time calibration method along with particle neutron detection. The time calibration method comprises the following steps: placing a graphite block at a certain distance in front of a neutron generator; controlling the neutron generator to emit neutron beams to the graphite block; measuring an alpha-gamma conformance flight time spectrum based on an associated particle detection technology; determining a spectrum peak formed by directly acting neutrons on the graphite block according to the measured alpha-gamma conformance flight time spectrum, and taking theconformance time corresponding to the spectrum peak as measurement reference time; and carrying out neutron detection on a detection object to determine content characteristics of related elements inthe detection object. According to the method, the problem that the calibration time of a Si semiconductor detector used for measuring the accompanying particles along with temperature and time changes is unstable is solved, the detection positioning precision of the to-be-detected object is ensured, and accurate analysis of element characteristics in a detection area is realized.