Bifurcated granular flow in a 2D channel with two lateral exits is numerically investigated by the discrete element method. Under the fixed inflow rate condition, the outflow rate is equal to the inflow rate in the dilute flow state and rapidly declines when dilute-to-dense flow transition (DDFT) occurs. The flow rate and the transition can be controlled by adjusting the sizes of the two exits. These observations can be explained by the relationship between the flow rate and the packing density in the bottleneck region under the fixed grain condition. Beverloo's formula is valid to describe the dependence of the dense flow rate on the exit size for bifurcated and non bifurcated granular flows. The packing density in the bottleneck region plays a crucial role on the flow state. In specific, DDFT occurs at 0.6, and the dense flow terminates at 0.79. (c) 2021 Elsevier B.V. All rights reserved.