The purposes of this research were 1) to study the components and indicators of critical thinking skills and elements of learning model by documentary research and 2) to study environmental factors that affect the development of critical thinking skills for high school students including 1. Student opinion study. It is exploratory research. The target group are high school students in 5 schools under Department of local administration total 100 students by purposive sampling. Collect data using a questionnaire. Data were analyzed using mean and standard deviation and 2. Group discussion with teachers who teach computational science. The target group are teachers who teach computational science in secondary level in schools under Department of local administration total 10 teachers by purposive sampling. The research results were as follows: 1) Components and indicators of critical thinking skills consist: 1. Identify problem 2. Collecting information 3. Credibility of source of information 4. Hypothesis 5. Inference. The components of the learning model consist: 1. Principles 2. Objectives 3. Syntax 4. Content 5. Social system 6. Principles of reaction 7. Support system 8. Application 9. Measurement and Evaluation and 2) Environmental factors that affects the development of critical thinking skills for high school students, it was found that 1. Learning at present should combine communication devices that are portable wireless devices and widely used, such as mobile phones, smartphones, tablets, etc. in both face-to-face and online learning. 2. Learning activities to develop critical thinking skills for students should be use cooperative learning.