He will deliver a speech at the summit, in which he will explain Iran's high capacities for trade relations, according to the president's deputy chief of staff for communications and information, Parviz Esmaeili, IRNA reported.
"The president will hold bilateral meetings with the prime minister and other senior officials of Armenia to discuss the most important issues regarding Tehran-Yerevan ties and the latest status of agreements and joint projects," he added.
On the sidelines of the event, Rouhani will hold separate talks with other participating heads of state about key areas of common interest as well as regional and international issues, Financial Tribune reported.
The president will head back to Iran on Tuesday evening.
The Eurasian Economic Union includes Armenia, Belarus, Kazakhstan, Kyrgyzstan and Russia. Iran is in the process of establishing a free trade partnership with the EEU countries after an agreement was signed in Kazakhstan in May 2018.
The free trade arrangement is planned to be in effect for four years, under which EEU will grant Iran tariff concessions on more than 500 items by October end.