A three-dimensional coupled model for particle inertial migration in the presence of micro flows is proposed and implemented. In the present model, the kinetic theory based lattice Boltzmann method is used to describe the fluid flows, and the Newton dynamics equation based model is used to describe the translation and rotation of the particle. The fluid and particle model are coupled by the LBM bounceback scheme based moving boundary method. The processes of particle settlement under gravity and particle rotation in the condition of Couette flow take place. The reliability of the present model and algorithm is validated through comparisons between the present simulation and the benchmark tests in the literature. The simulations of particle migration with various radii in an annular curved channel are performed, and the classic velocity distribution of the secondary flow in the channel cross-section is reproduced successfully. The mechanism of the particle radius influencing the particle equilibrium position in the curved channel is discussed. The results show that the particle equilibrium position in the curved channel will approach to the channel inner wall with the increase of radius. The present model is of important value for detailed study of the particle dynamics in micro flows as well as for the design and development of new micro fluidic particle selective chips and devices.