This study aims to evaluate the effect of using accounting information systems on quality of financial information for service sector company in Gaza strip . Also , in order to measure and evaluate feasibility of using accounting information system in service sector in Gaza Strip , in order to know constraints and problems of using accounting information system in service sector in Gaza Strip . To achieve objectives of this study and complete practical part, we used analytical and descriptive approach , for collecting data related to theoretical part . We used questioner to collect primary data related subject of this study , and analyzes data by SPSS statistical program and use of statistical processors and tests , for getting signs to support subject of study , the questioner distributed for all accountant in service sector company in Gaza Strip who prepare financial statements. The study revealed that , size of company , revenue level and size of capital has important effect to company using of accounting information system . Also using of accounting information system will lead to perform quality characteristics of financial information and increase quality of that information such as accuracy , relevance , reliability and timelines of information. The study provided a set of recommendations the most important from them : service company in Gaza Strip that has big capital , number of workers and revenue they recommended to apply advanced accounting information system for reaching the greatest benefits from that systems, service sector company must invest part of revenues to develop accounting information system, to provide best services to increase revenue company.