Abstract: The lane-changing rules are proposed on the basis of features of lane-changing behaviours in the two-sided type C weaving section. The multi-lane cellular automata model is adopted to investigate traffic flow in such a weaving section. The phase diagram is obtained by numerical simulation with different weaving lengths. It is shown that the weaving length has negligible effect on traffic states of the weaving section when traffic flows of both main road and on-ramp are free. However, the increase of weaving length can improve the traffic states of on-ramp when the traffic flow of main road or on-ramp is congested. Furthermore, the distributions of density, velocity and lane-changing frequency of vehicles are discussed in the case of free flow of main road and large on-ramp flux. It is found that lane-changing behaviours occur mainly on both merging and diverging areas and lead to local congestion correspondingly.