A new experimental fluidized bed reactor was investigated and designed which has been widely utilized for fast pyrolysis under different temperatures (T=727–973 K).The stresses of the reactor cylinder are analyzed using finite element method(FEM, ANSYS Inc., U.S.A ) based on the safety assessment, and the cylinder is designed for installing scheme. The result of ANSYS analysis shows that the stress unstable positions are nearby both ends of the cylinder. The results of analysis are shown that the designing stresses are not beyond the allow able ones. So the designing parameters can possess sufficient reliability, and the design scheme can completely satisfy the strength requirement. Certainty of the stress could offered the valuable instruction for the application of the equipment on industrial scale-up.