The invention relates to the technical field of computers, and provides a method and a device for extracting data of limited Web databases. The method includes enabling the device for extracting the data to acquire an attribute value in a Web database query interface; generating and transmitting query requests to the limited Web databases; parsing query feedback web pages and extracting the query data; updating data in local databases according to the query data; analyzing the local databases by the aid of algorithms based on EdaliwdbFCA (extract data from limited Web database based on formal concept analysis) and generating next groups of query attribute values; completing data extraction when the numbers of the query data are equal to preset thresholds. The device for extracting the data comprises a query attribute value acquisition unit, a query unit, a parsing unit, a data updating unit, a query attribute value generating unit and a query completing unit. The formal concept analysis method can be used for extracting the data of the limited Web databases on the basis of the attribute value query interface, and accordingly the high-quality data can be extracted from the limited Web databases. The method and the device have the advantages of good stability and high efficiency.