USA during the years of nuclear conflict, forced all Iran`s trade participants to decrease their trade part. Yet, during the same years, china, on the contrary, multiplied its trade part with Iran and satisfied Iran`s need and decreased sanctions` press on it. The paper, using process tracing technique, intended to study the question: why did Obama fail in forcing China to follow the sanctions against IRI? What may be regarded as his limitations in the field? As shown in the study, many decades of extraordinary economic development have put china in such a position that American tools of power such as press, threat, sanction and diplomacy may not be effective on China.