Mr Xi, tipped to become China's next leader, appeared in public on Saturday.
His failure to attend a series of meetings with foreign figures had fuelled feverish speculation over his health and a potential power struggle.
China is due to hold a party congress next month that will see major changes in the top echelons of leadership.
However, no date has been set for the meeting, which is being watched closely.
Mr Xi will attend the opening ceremony and ''some other important activities'' of the 9th China-Asean expo in the southern city of Nanning later this month, Xinhua news agency reported.
It is not clear if Mr Xi will be meeting leaders from the 10-nation regional bloc who will be at the event from 21 to 25 September. Burmese President Thein Sein is among those scheduled to attend.
Mr Xi cancelled meetings with four foreign dignitaries visiting China in the past fortnight, including US Secretary of State Hillary Clinton.
The uncharacteristic move in a country highly conscious of protocol sparked off a series of rumours over the state of Mr Xi's health, with suggestions ranging from a back injury to more serious conditions.
His ''disappearance'' and the lack of an official statement, coupled with there being no clear date for the party congress, also prompted speculation of a power struggle within the Communist party.
Some analysts said that some of the seats on the nine-strong politburo Standing Committee could still have been unallocated.
There have also been suggestions that the number of seats for the top leadership ranks may be reduced from the current nine to seven.
On Saturday, China's official news agency carried a brief report of Mr Xi's visit to the China Agricultural University in Beijing with a photograph showing the vice-president smiling and walking with other officials.
On Thursday, Mr Xi was cited in state media for the first time in 12 days, expressing condolences over the death of a former general.
During his absence, searches for Mr Xi's name on China's Twitter-like weibo micro-blogging sites were blocked.
China's Vice-President Xi Jinping will attend a China-Asean trade event, state media say, after emerging from an unexplained two-week absence.