The purposes of this research were to study the current situation and to compare the consequences of the Child Development Centre teachers on classroom action research-based instruction. The sample was 81 teachers of the Child Development Centre of the Local Administrative Organisation, derived from multi-stage random sampling. The instruments were the semi-structured interview form, and the measurement form of learning management outcomes, which the validity was between 0.80-1.00 and reliability was 0.968. The data were analysed by percentage, mean, standard deviation, content analysis and independent t-test. The results showed that 1) most teachers conducted informal classroom research to solve children’s behaviour problems and to increase the development of children. They usually utilised their research than others, but still not much. 2) the consequences of the classroom action research-based instruction were significantly higher than the standard requirement instruction at the .05 level of significance. The outstanding results have been discussed.

In Thailand, in-service teachers’ professional development has been implemented through the Professional Learning Community (PLC) program for more than four years to develop teachers’ sustainably. The sustainable development program has spread across the country in the Thai Teacher Council network. The research goals are as follows: (1) to evaluate the causes and results of the Professional Development Program in the form of a Professional Learning Community conducted by the Teachers’ Council of Thailand and (2) to analyze factors affecting success and sustainability of the teacher professional development project. Within the study, 490 samples have been collected from the relevant parties. The respondents have completed the questionnaire and participated in the interview. The research results have revealed that the project is essential for teachers and education personnel. They change the teaching and learning approaches, as well as positive thinking skills; moreover, the students also increase academic achievements.