GUI(Graphic User Interface) have an influence on end-user environments in information system. Consistency is one of the most important GUI characteristics. Consistency should apply across the different media which form the total user interface. User can get a lot of benefits through consistency. To achieve consistency of the total interface, the interface standards are very important. The goals of this study is to suggest GUI's development guidelines through analysis of real fields using ERP package in a electric assembly line. The guidelines fall into four functions: inquiry, registration, modification, deletion. The guidelines can be used for better system development later and as verification tool in GUI development.