The Prime Minister met with Chinese entrepreneur Jack Ma, who owns Alibaba, China's version of Amazon.
His companies, the PM said in a tweet, had $157 billion of online transactions last year.
The Global Times newspaper's criticism of the UK is stinging given that David Cameron has spent two days courting China's leaders.
David Cameron's visit to China has not been easy to arrange with the pressure for the trip coming from the British.
David Cameron hopes to mend relations with China as he brings a large trade delegation with him.