During his second presidential tenure，President Obama once again adopted diplomatic solution to the Iranian nuclear dispute as a priority option，which also given rise to the attitude changes of Iran government，facing dire economic difficulties. Iran and the “P5 +1” countries（the United States，China，Britain，France，Russia and Germany）restarted a new round of Iranian nuclear talks，and Almaty Dialogue was fruitless，but entered a substantive stage in bargaining. Iran and the international community for advocating “moderate walking route” Rowhani was elected Iran’s new president reacted positively. Iranian foreign achieved rapid transformation into “constructive interaction with the world，” the new era. The new Foreign Minister Zarif has played an important role in “ice-breaking” development in the US-Iran relations，signing the First Phase Agreements of the Iranian Nuclear Issue in Geneva and other major diplomatic achievements that Rowhani’s government made during the first-hundred-day’s regime. Iranian nuclear issue is rapidly forward along the right track for a diplomatic solution，but there are still many obstacles ahead.