"I have good reason to believe that this project will soon see the light of day," he said in a speech to a business audience.
Couillard is on a trade mission to China along with Ontario Premier Kathleen Wynne and Prince Edward Island Premier Robert Ghiz.
Despite his optimism, Couillard was still cautious at a news conference when talking about the possible Montreal-Beijing flights.
He said the approval process in China is very complicated and hasn't yet been settled. He called the possibility of the flights "realistic."
"If it were in the bag, you would know," he said.
A meeting is scheduled on Wednesday involving Air Canada executives, Chinese civil aviation authorities and James Cherry, head of the Montreal airport authority.
Cherry said the flights would be operated by Air China, a partner of Air Canada (TSX:AC.B).
He added that figures indicate there are enough passengers to make the route profitable.
"The numbers are convincing," he told a news conference.
Monday was also a busy day for the Quebec delegation accompanying Couillard.
A total of 18 agreements and protocols were signed with Chinese partners in a number of areas, notably health, energy, green technology, the building sector, education, research and innovation.
One of the deals was for the creation of a partnership between Enerkem and the city of Shanghai to turn waste into ethanol. Economic benefits for Quebec are estimated at $325 million.
As well, the Xebec Adsorption company signed a letter of understanding for several biogas projects in China.
Omnia Technologies also signed a letter of intent for the construction of the first phase of a resort valued at $1 billion. HydroNov cut a deal worth $11.5 million for a hydroponic project for the production of fish and vegetables.
Cree United Power also signed a $600,000 agreement with two Chinese companies to build and operate a hybrid power plant in the Quebec Cree community of Whapmagoostui.