Speaking at a press conference on Wednesday, Ayatollah Mohsen Araki said 220 Iranian and 300 foreign guests will take part in the international event.
The WFPIST will organize the 31st edition of the International Islamic Unity in Tehran on December 5-7.
Ayatollah Araki said the theme of this year’s conference is "Unity and Requirements of New Islamic Civilization”.
He noted that more than 70 papers have been submitted for presentation at the international event.
There will programs on the sidelines of the conference, he added, including a number of exhibitions, a poetry recitation session in the holy city of Qom and celebrations marking the birthday anniversary of the Holy prophet (PBUH).
He said that participants in the conference will also visit the mausoleum of the late founder of the Islamic Republic of Iran, Imam Khomeini (RA) on Monday.
They will also meet with Leader of the Islamic Revolution Ayatollah Seyed Ali Khamenei on the second day of the event, Ayatollah Araki went on to say.
The annual event marks the Islamic Unity Week.
The 17th day of the month of Rabi al-Awwal in the lunar Hijri calendar, which falls on December 6 this year, is believed by Shia Muslims to mark the birth anniversary of Prophet Mohammad (PBUH), while Sunni Muslims regard the 12th day of the month as the birthday of the last prophet.
The interval between the two dates is celebrated every year as the Islamic Unity Week.
Imam Khomeini (RA) declared the occasion as the Islamic Unity Week back in the 1980s.