The major goal of this project was to review and examine all the elements, such as the process of implementation, experimental results, and laboratory quality system, which influenced the quality of monitoring data of the proposal titled “The Environment Monitoring of the Water Quality in the Northern, Middle, and Southern Area of Taiwan”. The reviewing of monitoring data quality of environmental water from January to December in year of 2009 had already been finished according to the annual goal of this work, and the access reports were already submitted to Environmental Protection Administration office every month. The implementations of management, evaluating and analysis of data quality of environmental water were also finished, including stipulating the quality goals of monitoring data, reviewing and audition of the Quality Assurance Project Plans (QAPjPs) and Standard Operation Procedures (SOPs) for the proposal “The Environment Monitoring of the Water Quality in the Northern, Middle, and Southern Area of Taiwan”. Also attended the working conferences of the plan, executing checking in on site sampling work for 179 times / 232 person-days and in laboratories for 123 times / 158 person-times, held blind tests for 4 times, assessed the technology of sampling staffs and set up the list of qualified personnel, determined and confirmed the function of measuring instruments used in sampling field and set up the qualified tabulation for this work. In addition, we also held ” The Discussion Meeting of Quality Assurance Checking Results” for 4 times, held the trainings in technological practice to quality-control and sampling staffs and analysts, evaluating and reviewing the work of environmental monitoring of the water quality and proposing 6 special reports, offering a professional person that kept in touch with Environmental Protection Administration for checking the water quality monitoring programs. In assisting with establishing environmental water quality monitoring e-annual report and information-services, the calculation modes, brief illustrations, descriptions, and the suggestions of charts compiling in the annual reports of all kinds of water bodies were proposed in this plan. During the executive process of this plan, it was requirement that the improvement and the necessarily processing program should be implemented by the contractors while a fault that might influence the quality of monitoring data was made from them. Moreover, from the executive result of this work, it revealed that the quality of data could be held effectively while personnel's technology and instrumental quality had been required rationally in advance. Generally speaking, besides of cooperating with this plan, if the contractors could strengthen self-checking even more, the promotion of the quality of monitoring data would be more efficient.