The invention relates to Q345-grade anti-seismic steel and a method for producing the Q345-grade anti-seismic steel by virtue of a steckel mill, belonging to the technical fields of machining and forming of metal materials. The Q345-grade anti-seismic steel comprises the following components: C, Si, Mn, S, P, Nb, V, Ti, N, Als and the balance of Fe and impurities. The method comprises the steps of firstly heating a plate blank, spraying water to remove phosphorous, continuously finishing rough milling and precision milling on a double-stander compact steckel mill, feeding the finely milled steel plate to a reeling machine to be reeled, and naturally air cooling to the room temperature, so as to obtain the Q345-grade anti-seismic steel with high strength and low yield ratio. By adding microalloying elements such as Nb and V into the Q345-grade anti-seismic steel, the strength and the toughness of the Q345-grade anti-seismic steel are effectively improved. According to the Q345-grade anti-seismic steel produced by virtue of the method, the potential of the double-stander compact steckel mill manufactured by Kunming iron and steel Co., Ltd. is adequately explored, the variety of plate strip products is expanded, and the product structure is optimized.