Failure of Management Information Systems(MIS) could cause loss of enormous development cost and delay of timely re-action to changing business situations. A testing must be performed in order to detect and correct possible errors in advance as well as to verify whether MIS was developed faithfully according to business requirements. To set up criteria for effective testing of MIS, a modeling for trustability to present basic performance of testing is needed. A model on the basis of testing power and trustability is very useful in finding this testing method and combination. To verify the effectiveness of analysis method extracted by a trustability model, a trail experiment where performance comparison is possible under various situa-tions is necessary. So, we research on effective testing in order to resolve the failure of MIS in a preliminary stage. First of all, we point out some defects of both traditional testings related to MIS testing and application to trustability model with imple-menting a trustability model. An optimal testing model is implemented and proposed on the basis of the trustability model with some configurations for a trial testing. Finally, it is analyzed how this designed trustability model is effective.