This study aimed to identify the psychometric properties of "Burney objective formal reasoning scale and its application on students of grades nine and eleven from Al Batinah North region. Descriptive approach was followed, and the researcher used suitable statistic methods to answer the questions of the study. The sample of the study consisted of 446 students. The validity of the scale was verified by three methods: the face validity, the criterion-related validity and the factor validity, the results showed that the scale has acceptable validity ratio. The results also, viewed the three- factor structure of the scale. The reliability of the scale was examined by using internal consistency, and test- retest method. Cronbach's alpha was found 0.748. The reliability coefficient was examined by using test- retest method was found 0.756 and these ratio were considered acceptable validity indication for the scale. Regarding, the percentage of the students, the results showed that students of grade nine and eleven in formal thinking in two variables class and gender, results showed that students of grade eleven have more percentage in formal thinking than students of grade nine. This concludes that as students move from one grade to another, they are gain knowledge skills. Moreover the study shows that the percentage of formal thinking with females is higher than with male, and the researcher attributes that to several reasons like motivation. Regarding, the percentage of those from the sample who reached the stage of the formal thinking, it was only 4.48%, and this percentage is of course very low comparing to the size of the study sample. The results were discussed in the light of theoretical frame and the previous studies, and some of recommendations and suggestions have been reached.