The objectives of this research were to develop and investigate the feasibility and usefulness of an effective internal supervision model of school under the secondary Educational Service Area office 22 by studying 355 populations from the multi stage sampling, were 34 school directors and 321 teachers. The instrument using for data collection included rating scale questionnaire with the validity 1.00, the discrimination is between 0.43 – 0.98 and the reliability is 0.99.The data were analyzed by using frequency, percentage mean and standard deviation. The research results were as follows: 1. The Effective Internal Supervision of School under the Secondary Educational Service Area Office 22 included 4 factors that have effected to the internal Supervision, scope, and the effectiveness of Internal Supervision process. 2. The Effective Internal Supervision of School under the Secondary Educational Service Area Office 22 is appropriate and the benefits to the opinions of school administrators and teachers in overall and in each level were at the highest level. When considering in each aspect sort by average from high to low found that effectiveness of internal supervision, factors that affect internal supervision, internal supervision process and the scope of internal supervision respectively.