The aim of this research is to identify the correlation between preservice science teachers' educational philosophy approaches and thinking, decision making and planning processes during the construction process of science class. Sample consists of 90 preservice science teachers from Hacettepe University Faculty of Education Department of Science Education. This research is a case study and both quantitative and qualitative methodologies were used. Questionnaire was used in quantitative dimension as a data collection technique. Measurement tool is "Philosophical Preference Assessment Form Scale (PPAF). Observation, interview and documentation were used as qualitative techniques of this study. Most of the preservice teachers are under the influence of progressivist and experimentalist educational philosophy trend (% 72). Besides this, the application process of progressivist and experimentalist preservice teachers in teaching and learning environment show that they are under the influence of idealist and realist trends. The gap between thinking-decision making and planning processes emphasize the need of planning research studies which investigate the correlation between philosophy in teacher education and application processes and reconstructing preservice and inservice programs.