In this paper, dynamic floor field is introduced to investigate the characteristics of bicycle flow. To embody the features of bicycles and riders, the repulsive force among the riders and the velocity effect are taken into consideration in this new model. A new concept called lane-changing cost is proposed to study the effect of driving styles, and a new lane-changing rule is proposed based on the traffic environment comparison. The simulation results show that 1) the model can accurately describe the bicycle flow, and the obtained statistics accords with empirical data; 2) the capacity of the road of per unit width deceases as road-width increases; 3) aggressive driving style substantially increases the lane-changing times, which reduces the capacity of the road.