Abstract: The relationship between the activities of earthquake swarms and small earthquake series in Shandong area and mid-strong earthquakes in its surrounding area since 1970is analyzed.The research shows that the activities of earthquake swarms and small earthquake series have seismic precursor significance to mid-strong earthquakes.The relations between them are statistical analyzed,and the abnormal indexes that have practical significance to annual or mid-short term prediction of mid-strong earthquakes in surrounding area are given.