The statistical relationship between moderately strong earthquakes in North China， Jiangsu and its adjacent area from 1962 to 2010 and the earth rotation acceleration has been investigated． The results show that all of the strong earthquakes ( MS ≥6. 0 ) in North China occurred in the rising period of earth rotation acceleration and its second half year． 63% of the earthquakes occurred in the rising period of 4 years after the start． 11 moderately strong earthquakes (MS≥5. 2) in Jiangsu and its adjacent area occurred in earth rotation acceleration's rising period，and 64% of the earthquakes occurred in the rising period of 3 years and 10 months after the start．