Abstract: The effect of technology parameters such as initial rolling temperature, deformed speed, draft distribution and Interpass time on grain size has been simulated analyzed and calculated using established the simulation system for grain size of hot rolled plate and strip of microalloying steel. And based on this, a Back Propagation (BP) network for the relation between grain sizes and technology parameters and the technology optimization model are established to completely utilize static recrystallization mechanism, fine grain size of plate and strip of microalloying steel.