The seismicity data of moderate or small earthquakes in North China are used to space scanning of seismic inhomogeneous degree GL-value.Characteristics of mid-short term anomalous changes of the value before mid-strong earthquakes in the region are studied.The result shows that the mid-term anomalous area of the GL -value obviously contracts or disappears in mid-short term of about 1 year before moderate or strong earthquakes in generally.The anomalous area appears again in several months before some earthquakes.Some problems about mid-short term prediction by using the GL-value are also discussed.