The current research aims to use the Rasch model in the preparation of the Jane Cirillo test of the mental ability of university students . To achieve this goal, the researcher followed the steps of preparing the test, starting with the translation of the test items and instructions from English into Arabic, and then re-translating them from Arabic into English. The researcher took the amendments made to the translation when presented to the translation experts, and then presented the instructions of the test and its items to an expert specialized in Arabic, and after taking his observations, it was presented to the arbitrators in educational psychology, measurement and evaluation, to ensure the availability of the appropriate characteristics for it and for it’s alternatives in terms of form and content, and the researcher took their opinions, and made some amendments in light of their observations, and all the test items are logically valid to measure what they developed in order to measure. To ensure the clarity of the instructions and items of the test and to determine performance time , the test was applied to a survey sample of (50) students, and it appeared that the instructions and items of the test are clear, and the performance time was limited to (43) minutes. The test was applied to a sample of (400) male and female students (Baghdad University/Morning Study) who were selected in a multi-stage random sample method, and the researcher relied on the one parameter Rasch model, which is one of the models of Latent Trait theory to analyze the test items , and to verify the assumptions of the model, the researcher followed the following