The technology acceptance model (TAM) is a lot of cited in information technology adoption and usage researches. But TAM has been conducted primarily in volitional environments of the adoption of new technology. This paper discusses technology acceptance in accounting information systems to examine TAM with Characteristics of Organizations and Individuals in mandated using Combined Guard System. Combined Guard System is a scientific guard system that is composed of automated surveillance system, automated sensing system and control system. GOP Scientific Guard System is operated by GOP unit in Korean Army O Division from 2006. In this study, using the extended technology acceptance model, we have analyzed factors which affect the usage intention of GOP Scientific Guard System in mandated using environment. Based upon previous researches, we have selected Support of management unit, Training, Perceived Risk, Subjective Knowledge and Computer Self-efficacy, perceived usefulness, perceived ease of use, and usage intention as variables and proposed a research model. We collected 253 survey questionnaires from Korean army officer and soldier who are serviced at GOP unit in O Division, and analyzed the data using SPSS 12.0 and SmartPLS 2.0M3. According to the results by PLS analysis, According to the results by PLS analysis, Training and Subjective Knowledge did not affect Perceived usefulness, but the other hypotheses were accepted. And Perceived usefulness, and Ease of use influenced the Usage intention. The results of this study will increase Characteristics of Organizations and Individuals on GOP Scientific Guard System and eventually contribute to establishing the activation of Combined Guard System.