Speaking to reporters in the Austrian capital on Monday, Wang Yi said a number of remaining issues still need to be resolved despite the new progress.
He said all of the parties involved in the negotiations, particularly Iran and the United States, should make up their mind as soon as possible.
A deal is within reach, the Chinese minister added.
Yi has joined the high-profile talks in Vienna following his Russian counterpart Sergei Lavrov and Britain's Foreign Secretary Philip Hammond.
Iran and the Group 5+1 (Russia, China, the US, Britain, France and Germany) are busy negotiating to clinch a lasting deal, known as the Joint Comprehensive Plan of Action (JCPOA).
The two sides have been negotiating over the past 22 months to end more than a decade of standoff over Tehran's civilian nuclear program once and for all.
Last week, Iran and the sextet gave themselves an extra week beyond an end-June deadline to nail down the details of the likely accord.
Iran's Foreign Minister Mohammad Javad Zarif and US Secretary of State John Kerry, who have held several rounds of meetings in Vienna over the past three days, have both announced that the negotiators have never been closer to a deal.
According to a source familiar with the talks, the final deadline for the comprehensive accord falls on late Wednesday or the early hours of Thursday, July 9.