The bending performance of bamboo scrimber beams strengthened with fiber reinforced polymer composites (FRP) was analyzed by finite element software ABAQUS. The finite element simulation results are coincident with the experimental results, and the load-displacement curves are consistent and the cross-section strain development process is basically similar. The finite element prediction of bearing capacity has a good accuracy. When the load of 70 kN is applied, the errors of the strain of the cross section is within 13.96%. The maximum error of the predicted bearing capacity is 9.04%. The FRP reinforcement realizes the stress redistribution for bamboo beams and the performance of bamboo in the compression zone may be developed with more efficiency. Moreover, the influences of the aspect ratio, the number of the FRP layers and the FRP type on the bending performance of bamboo beams were investigated by parametric analysis. The increase of the number of FRP layers has a significant improvement effect on the ultimate bearing capacity and cross-sectional stiffness of the bamboo scrimber beams. With a given number of FRP layers and FRP type, the increment of ultimate bearing capacity and cross-sectional stiffness increases as the height of the cross-section reduces, and the enhancement effect of CFRP is better than that of the BFRP with the same cross-sectional height and the same number of FRP layers.