Abstract: Using the 50W800 non-oriented silicon steel cold hard plate produced on the LCP production line of Jiugang as raw material, the bell annealing process was simulated by using a box-type resistance furnace in the laboratory, and the effect of annealing process on the microstructure properties of 50W800 non-oriented silicon steel was studied. The results show that there are a large number of small grains inside the 50W800 non-oriented silicon steel when the annealing time is 5 h. When the annealing time is 10~15 h, it can be seen that the internal grain size is significantly coarseened, the grain uniformity is better, and the magnetic properties are better when the annealing time is 15 h. When the annealing time is extended to 20 h, abnormal grain growth will occur; When the annealing temperature is 660 °C, there are a large number of small grains in the finished product. When the annealing temperature reaches 750 °C, the abnormal growth of grains obviously occurs, destroying the uniformity of grains, thereby deteriorating the magnetic properties. The grains of electrical steel at the heating rate of 1 ℃·min⁻¹ are both large and uniform, so that the iron loss is lower than that of the finished product with a heating rate of 5 ℃·min⁻¹ and 10 ℃·min⁻¹.