This study aims to reveal the performance of students in grade 7 in the mathematical representation for the concept of Ratio and proportionality to find out the extent of their understanding for Ratio and proportionality and its relationship to the procedural knowledge. The researcher has to prepare two tests, one in the mathematical representation, and the second in the procedural knowledge in Ratio and proportionality while all the questions were in article forms. Also, it has been verified from the reality of the two tests by a group of arbitrators. In addition the stability of tests by has been verified using the method of internal consistency where the coefficient of Cronbach Alpha for the tests are (0.68) and (0.73), respectively. The study consisted of 302 of students distributing at (12) divisions on (5) schools which belong to the directorate General for Arts and Education in Al-Dhara region in Sultanate of Oman. The study yields the following results - Decline in the performance of students in grade7 in the mathematical presentation for Ratio and proportionality, relatively low in procedural knowledge in Ratio and proportionality. - The performance of students in low mathematical representation in up to twice the percentage of students in low in procedural knowledge. However, the percentage of high level performance of students in procedural knowledge is up to three times the percentage who has high performance in mathematical presentation. - All students who have high performance in mathematical representation also have high performance in procedural knowledge high, but not all the students, who have high performance in mathematical representation, perform in highly procedural knowledge. - No significant statistically difference between the averages in each of the mathematical representation and procedural knowledge, notary that the performance of female was relatively better in mathematical representation and procedural knowledge.