The UK's first direct flights to the home of China's Terracotta Army launch this summer.
Tianjin Airlines will fly between Heathrow and Xi'an, where the popular tourist attraction is located.
It is one of a number of improved air links between Heathrow and China this year.
Hainan Airlines is to begin Heathrow-Changsha flights, while Beijing Capital Airlines is to convert its existing charter operation to a scheduled route to Qingdao.
These services will provide more than 217,000 new seats every year for passengers travelling to and from China, and an additional 6,700 tonnes of cargo space for UK exports.
Heathrow already offers more than 100 direct flights to Chinese cities every week.
Fifty-five of these go to Hong Kong, 22 to Shanghai, 20 to Beijing, 10 to Guangzhou and two to Qingdao.
John Holland-Kaye, Heathrow chief executive, claimed the importance of the UK's links with China demonstrates the need for the third runway project to go ahead.
He said: "China is booming and the appetite for British goods is stronger than ever.
"We are delighted to welcome these new airlines and routes.
"However, it is clear that the UK's access to these Chinese markets continues to lag behind our European rivals.
"Our nation's biggest port is full and new routes from the UK to huge markets like Changsha and Xi'an are sadly the exception not the rule.
"If the UK is going to be a global trading powerhouse after Brexit, we need to expand Heathrow now, opening up to 40 new trading links that will help all of the UK thrive."
Ten figures from the 2,200-year-old Terracotta Army are currently on display at Liverpool's World Museum.