By using lotus notes server-client system, the database related to general information of cancer patients, radiation treatment simulation, cancer treatment information and all kinds of information of radiation oncology department need to be developed for effective information management and also user interface was developed for input and output of information. This database also could be used for clinical study, patient care research and medical education. By the development of this electronic chart of the department of radiation oncology, the clinic datum and medical information management could be connected effectively and treatment information according to treatment machine also could be acquired and contributed for improving treatment efficiency, cutting down the waiting time for clinic.