To set ¡§Electronic Government¡¨ into action becomes common practice all over the world. The aims of ¡§Electronic Government¡¨ are to link all government agencies, citizens and information through networking and to establish real time and interaction system services. It improves government operational procedures, promotes service efficiency and quality. There are ¡§Government to Government¡¨, ¡§Government to Business¡¨ & ¡§Government to Citizens¡¨ according to the applications of electronic business. To implement the Government to Government program, The government has deployed a¡§Electronic Gateway Information System¡¨and an E-government Common Platform Guideline to integrate interdepartmental information and simplify related operating processes. There are many important influences to lessen the need for redundant copies of official documents and to improve the efficiency of administrative procedures. The study takes Bureau of National Health Insurance Kao-ping Branch, which practice National Health Insurance in Taiwan as an example to research interdepartmental information sharing and services. That includes its performance, benefits, influential factors, and difficulties of implementation to try to seek the key problems and propose some suggestions for implementation of ¡§Electronic Gateway Information System¡¨. For examples establishing the interdepartmental integrated association, improving the system quality, protection personal detail security, etc.