The reinforced concrete beam with negative Poisson ratio effect was designed and fabricated by changing the square stirrup of reinforced concrete into six-ribbed structure and star-shaped structure. The flexural performance of concrete was simulated by three-point bending test and drop hammer impact test, and its deformation behavior and Poisson ratio were analyzed by digital speckle correlation method. The results show that the stirrups of six-ribbed structure and star-shaped structure can improve the flexural capacity of concrete, delay the development of cracks, and improve energy absorption rate and flexural toughness. The flexural capacity and coefficient of flexural toughness of star-shaped reinforced concrete are up to 22.6 kN and 3.86 MPa, respectively. With the change of stirrup structure, the flexural performance of concrete is enhanced, but the Poisson ratio decreases, and the phenomenon of negative Poisson ratio even appears in reinforced concrete with star-shaped stirrup. The minimum Poisson ratio can reach －0.03.