He made the remarks at the meeting attended by leaders of six countries which helped broker the Iranian nuclear deal, an event on the sidelines of the fourth Nuclear Security Summit here.
Calling the Joint Comprehensive Plan of Action reached on the Iranian nuclear issue a "milestone," Xi called for full implementation of the Iranian nuclear deal which downsizes Tehran's nuclear program in return for Western sanction relief.
"We should stick to the political commitment and make sure the deal is implemented as it should have been," Xi said, adding that any "external interference" should be eliminated.
Iran reached the Joint Comprehensive Plan of Action last year with the "P5+1," namely Britain, China, France, Russia, the United States and Germany, over its nuclear program after over 18 months of marathon talks.
China has always been "an active participant, constructor and contributor" in the solution process, Xi said.
"We stand ready to work with all related sides to push forward the implementation of the deal," he said.
He also stressed the importance of strengthening the global security governance in today's world where hot issues keep emerging.
The Chinese president said that dialogue and negotiation should be the best choice in solution of hotspot issues and cooperation and coordination among major countries proves effective to settle serious disputes.
"Moreover, justice and equity should be the underlying principle for reaching any international agreement," he said. "The double standard will not lead anywhere."