Because of sharing and security,geographic data need to be processed,and data decryption is the primary means. Based on the availability of the processed geographic data,the impact of decryption on the data is analyzed,and a geographic data availability evaluation model is constructed. The model comprehensively evaluates the processed geographic data from three aspects of visualization effect,reliability and effectiveness to obtain an evaluation model and rating scale. Through the proposed model,it is possible to comprehensively evaluate whether the processed geographic data is available and whether the data processing method ( decryption algorithm) is reliable.