Saudi Arabia & United endowed with a lot of oil resources and potential cultural status quo operated among the Arabic countries ,thereby that country counted as one of cutting edge player in the Middle East scene, consequently it plays crucial role in view point of USA as a partner, meanwhile  the extensive range of petrodollars earned to be allocated to the modern armament and military equipment procurement via USA, thus that outcomes brought about close and comprehensive military and security cooperation but both countries suffer from a gap due to political , ideological and cultural challenges in spite of eminent interests arisen by their close relationships within the last few decades as well.
The scenario of Iran hegemony and Shiite dominancy in the region including some domestic oppositions it pushes Saudi Arabia to the flank of USA , on the contrary the nuclear agreement concluded between Iran and 5+1 negotiators , the case forced Saudi Arabia to assume independent policy as a gist , it means that country reviews other alternatives to retain as an ally with exclusion of the USA ,but it seems that strategy may hardly distort the course of relationship with the USA & Saudi Arabia for the short period.
The current paper studies the security & strategic relationship between Saudi Arabia & United States of America by application descriptive – analytic methodology in order to define the agility and influence of concerning relationship to reinforce and sustain the security objectives of the both countries , initially the paper stresses to provide a definition of security term ,then to focus on the theoretical perspectives so as to develop the issue ,indeed it define the relationship of both countries by demonstration of the Middle East Changes, finally to reach mainly a logic conclusion.