Abstract: Based on binary collision approximation (BCA), combining molecular dynamics (MD) and kinetic Monte Carlo (KMC) simulations, a multi-scale simulation method was proposed to investigate the long-term evolution of defect and current induced by single particle displacement damage (SPDD). Within the studied time scale (106 s), three stages for defect evolution can be identified: In stage Ⅰ (1×10-11 s≤t<2×10-3 s) many point defects are captured by defect cluster; in stage Ⅱ (2×10-3 s ≤t<2×102 s) a great number of interstitials and vacancies in defect cluster recombine; in stage Ⅲ (t≥2×102 s) the number of defect tends to be stable, with only few small defect clusters emitting single interstitials or vacancies slowly. A novel method was proposed to calculate the heavy ion induced SPDD current for silicon device, and expressions are derived for calculating the increase of dark current of photodiodes induced by multiple types of defects. Based on the result of the evolution of the displacement damage defects, the SPDD current and its annealing factor were calculated. The annealing factor is consistent with the literature experiment result, indicating that the method developed could be used to evaluate SPDD current in silicon device.