A method for simulating a particle transport may include recording transport paths of inputted particles and determining an uncertainty of each of lattice cells based on the transport paths of each batch of the inputted particles, a lattice cell being a qualified lattice cell if an uncertainty of the lattice cell does not exceed a first threshold; determining a standard-reaching rate of lattice cells in a region of interest (ROI), the ROI including at least one lattice cell, the standard-reaching rate of lattice cells in the ROI being equal to a ratio of the number of qualified lattice cells to a total number of lattice cells in the ROI; and if the standard-reaching rate of lattice cells in the ROI exceeds a second threshold, stopping inputting particles, and outputting the transport paths of the inputted particles.