The fair saw the participation of 48 foreign countries and a "large number" of companies, according to the state news agency SANA.
The number of visitors' gates has also increased from three to 11 this year.
The fair is the Syrian economy's window to the world at a time vast swathes of territories returned under the government's control.
This round is the second to take place during the war, as last year's fair was the first after five years of pause due to the war.
This year the fair is being held at a time the entire capital Damascus and its surrounding, as well as the vast majority of southern Syria, have been recaptured by the Syrian army.
The Syrian government and its allies have been focusing recently on the reconstruction process, and the fair aims to encourage investments in that regard.
Kartali said the number of transportation buses increased to 3000 this year from 70 that were in service in 2017 to secure the transportation of people from Damascus to the fair site, which is around 300 km from Damascus.
He said that 1,722 companies participated in this year's fair, adding that this year the preparations were better than that of last year.
He pointed out that the fair constitutes one of the most important windows through which the government is attempting to communicate with friendly countries with the aim of introducing the "major investment chances" in Syria nowadays.
At the opening ceremony, Syria's Prime Minister Emad Khamis said, "as Syria has won in its war on terror, it will also win in the battle of rebuilding and reconstruction."
DAMASCUS, Sept. 6 (Xinhua) -- The 300th Damascus International Fair kicked off in the Syrian capital Damascus on Thursday, as the government is promoting opportunities for investment in Syria amid improved security situation.
The Syrian army is now preparing to launch a massive campaign against the northwestern province of Idlib, which is the last major rebel stronghold in Syria.
For his side, Fares Kartali, director of the General Establishment for Exhibitions and International Markets, said that this year the fair space was expanded to 93,000 square meters, an increase of 20,000 square meters from last year.