The objectives of this research were to: 1) study the current and desirable situations of supervision for graduate diploma in teaching profession program, 2 develop the internal supervision model using professional learning community for educational supervisor of graduate diploma in teaching profession program, and 3) evaluate the efficiency of the developed model.The samples were 49 educational supervisors and committees of graduate diploma in teaching profession program. The instrument was handbook of internal supervision model developed by using the professional learning community. Statistics used were percentage, mean, standard deviation, modified priority needs index, efficiency index, and t-test for dependent samples. The finding srevealed that: 1) The current situation of internal supervision of graduate diploma in teaching profession program was in "High" level. In addition, the desirable situation was found in the"Highest" level. When considering each aspect, it was found that the aspect with highest emergency need for development was the planning with the PNImodified of 0.40. The second one was the implementing with the PNImodified of 0.36. 2) The developed model was evaluated in the "Highest" level in terms of the propriety, feasibility, and utility.It was integrated in 6 steps including: (1) Preparing, (2) Planning, (3) Implementing, (4) Reflecting, Improvement, and Evaluation, (5) Reinforcing, and (6) Concluding and Reporting. 3) The results of the trials were: (3.1) The efficiency of process and product (E1 / E2) were84.67/ 83.00 which was higher than the specified criterion 80/80. (3.2) The posttest score was significantly higher than the pretest one at level of p-value <0.01. (3.3) The satisfaction on the developed model was in the "Highest" level. When considering each aspect, it was found that planning had the highest mean score, while implementing was found in the second order, and reflecting, improvement, and evaluation had the lowest mean scores.