In present time there is great demand for geographic information provided by internet. Therefore it comes to large development of internet applications which provide these services. Applications are built by many means however the majority destitute many defects. One of these defects is insufficient usability of new projects. This article describes methods of usability testing of GEOWEB through heuristic evaluation. This method was described by Nielsen and Molich in 1990 yet. It is testing with experts whose go through all heuristics and evaluate them. In usability testing this can be used instead of usability testing with evaluators. There is written eight groups of heuristics. First group is about environment of user interface, that describe duty of using basic function, actual data etc. The other group is about used technology that is supported. Next group examine errors. The system must inform user about errors, contain of errors and how to repair. Flexibility, esthetics and design describe all items of application. User-friendly chapter describes intuitive and functional control of application. Privacy section is about restriction in pro- vided maps. Help and documentation tests if is everything uncertain is explained there. Skills and usability control and freedom mean easy using of application. The last group is about list of maps. This list must be very easy for use to find all necessary maps. In the end of article is how to evaluate and write final report.