Thirty containers filled with British produced goods will set off on the 7,500-mile journey from Stanford-le-Hope, Essex.
Whisky, soft drinks, vitamins, pharmaceuticals and baby products are among the items being exported.
A DB Cargo locomotive will leave the DP World London Gateway rail terminal at 10.35am on Monday.
The DB Cargo locomotive will leave at 10.35am
Thirty containers filled with British produced goods will make the journey
We look forward to enabling and facilitating more trade between the UK, China and the whole world
Sultan Ahmed Bin Sulayem – DP World chief executive
After passing through the Channel Tunnel into France and on to Belgium, the train will call in Duisburg, Germany before InterRail pull the cargo through Poland, Belarus, Russia, Kazahkstan and arrive at Yiwu, eastern China on April 27.
It is departing almost three months after the first freight service from China to the UK arrived in east London.
The journey is cheaper than air freight and faster than sea freight.
The journey is cheaper than air freight and faster than sea freight
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The service is part of China's One Belt, One Road programme of reviving the ancient Silk Road trading routes with the West, initially created more than 2,000 years ago.
DP World chief executive Sultan Ahmed Bin Sulayem said that the first freight service from the UK to China is a "significant trade occasion".
The service is part of China's One Belt, One Road programme
He went on: "DP World London Gateway, one of the UK's largest logistics hubs, is designed and developed to ensure products can be both imported and exported from the UK via ship or train in a faster, safer and more reliable way than ever before.
"We look forward to enabling and facilitating more trade between the UK, China and the whole world."
International trade minister Greg Hands said: "This new rail link with China is another boost for global Britain, following the ancient Silk Road trade route to carry British products around the world.
"It shows the huge global demand for quality UK goods and is a great step for DP World's £1.5 billion London Gateway port as it also welcomes its first regular container ships from Asia."