Abstract: Due to the confidentiality of the geographical base map，the application of the medium scale geological maps to geological task and economic development is being excessively curbed at present.This paper studied security technology processing flow of public version of medium scale geological maps and formed key techniques of the workflow which includes removing classified information on geological map.The results have formed public version of spatial database which contained 1∶200 000，1∶250 000 and 1∶500 000 geological maps.It provided convenience on obtaining geological data to promote geological work and society-economy development.