Abstract: The O1 component of geomagnetic lunar daily variation is analyzed by the generalized method of Winch.First,the annual mean variation of D,H and Z elements at Sheshan Observatory during 1960-1988 are calculated by analysis of the data of hourly average values,then the data are re-analyzed after subdivision of quiet, medium and active periods according to seasonal and solar activities.The general features and seasonal variation of L(O1),the effects of the ionospheric and the oceanic dynamo on L(O1)and the contribution of solar activity to L(O1)are discussed,and the comparison analysis of the results is made between this work and those of some observatories abroad.