Environmental problems have been globally concerned by all countries. Such problems have been originated from human activities by overconsumption and overuse of natural resources. With consequently occurring of environmental degradation. In order to solve such problems, the environmental awareness has been recognized. Environmental awareness has been pointed out in Agenda 21 to achieve sustainable development and be implemented in the global communities in all sectors. Environmental awareness in Thailand has been set up as the national policy according to the National Economic and Social Development Plan since 1997 and also at the Thailand Business Council for Sustainable Development. The objectives of the study are to study factors of the current level of environmental awareness of employees involvement in the public limited company, and to propose effectively the descriptive capacity building model on environmental awareness utilized in the public limited company. The questionnaire set and in-depth interview were developed based on the relevant research studies for primary data collection and were applied to the operational and managerial level of one public company in Thailand focusing on point of view on environmental awareness concerned. Descriptive statistics were used for data analysis which presented in terms of percentage. The findings found that the effective internal factors are good attitudes towards environmental problems, intention to change behavior to be more environmental friendly, participation to the environmental issues, personal characteristics, and sufficient environmental knowledge. These factors are at the personal level which have the effective mechanisms including formal training, on-the-job training, knowledge sharing, environmental friendly activities, supply chain involvement, and roles and responsibilities assigned leading to the final output that employees would behave more on environmental friendly concerned both at workplace and his/her personal lifestyle. Another findings is the effective external factors in the company and society levels. At the company level, the effective external factors include company’s infrastructure, company’s culture, and company’s policy. These factors would be enhanced by environmental friendly infrastructure, environmental concerned department, organization collaboration, reward and recognition provided by the company, and benchmarking with other companies. The final output at this level would be the environmental policy implementation which is fully supported by the management team. At the society level, the effective external factors are society’s infrastructure, governmental policy, character of the society, culture with effective mechanisms including law enforcement, national and international environmental standard applied by the company. This lead to the final output of continuous business improvement at all times. Therefore, if these factors and mechanisms of all levels were well-function to be implemented, the effective descriptive capacity building on environmental awareness would be explicitly enhanced. This study further recommended that public participation should be highly considered to be involved in the implementation process to enhance the effective environmental awareness at all levels.