To investigate bicyclists’ behavior at unsignalized intersections with mixed traffic flow,a bicycle capacity model of borrowed-priority merge was developed by the addition-conflict-flow procedure.Based on the actual traffic situation,the concept of borrowed priority,in which the majorroad bicycles borrow the priority of major-road cars to enter the intersections when consecutive headway for major-steam cars is lower than the critical gap for minor-road cars,was addressed.Bicycle capacity at a typical unsignalized intersection is derived by the addition-conflict-flow procedure.The proposes model was validated by the empirical investigation.Numerical results show that bicycle capacity at an intersection is the function of major-road and minor-road car streams.Bicycle capacity increases with increasing major-road cars but decreases with increasing minorroad cars.