Representatives from the Chinese Super League are understood to have made the offer after visiting Manchester last month for the annual Soccerex convention.
The Manchester United midfielder, however, is said to have "politely" declined the incredible cash on offer and is determined to see his future at Old Trafford.
Mata has less than 12 months remaining on his deal and his camp expect the Red Devils to take up their option of extending that by a further year, to prevent him being able to leave on a free transfer next summer.
The Spain international is represented by his father, Juan Snr, who has been pushing the Red Devils since the end of last season to come to the table and discuss a longer term deal.
Mata joined United from Chelsea for a then club-record £37.1m back in 2014 and has since put down firmer roots in Manchester, opening a tapas and wine bar in the city-centre last year.
The former Valencia man earns a reported £170,000 per week and the 29-year-old is looking for similar terms, with United officials insisting boss Jose Mourinho has every intention of retaining the player.