A Monte Carlo ion implantation simulation method includes finding a unit cell in which an implanted trial particle is present, finding a basic cell in which the trial particle is present among basic cells that form the unit cell, finding a directional range in which the trial particle travels, obtaining collision candidate atoms with their locations from a database according to the found basic cell and directional range, setting a thermal vibration displacement for each of the collision candidate atoms that has not set thermal vibration displacement, calculating a collision parameter and free-flight distance for each of the collision candidate atoms, selecting, as a collision atom, one of the collision candidate atoms that has a collision parameter smaller than a predetermined maximum collision parameter and a smallest positive free-flight distance, and calculating a collision between the trial particle and the collision atom to find the after-collision location and momentum of the trial particle.