The Mayor, who is just over halfway through a six-day trade mission in China, took the opportunity to visit the M&S branch.
"It's so great to see a brand like Marks and Spencer, which is something I grew up with all my life, here in Shanghai", Mr Johnson said.
"It's a real sign of the strengthening of economic ties between London and Shanghai." Mr Johnson is visiting the country to promote investment ties between London and China.
Earlier in his visit the Mayor of London, who is learning Madarin, said British schoolchildren should be given the opportunity to learn Chinese.
The Chancellor George Osborne is also on a visit to the country to promote investment in the UK.