Microsoft suspended "mainstream support" of the product yesterday, meaning neither new features nor free help will be given to Windows 7 users.
The company will continue to patch security vulnerabilities until 2020, state-run China Daily reported.
The US-based company hopes retiring the 5-year-old operating system, which runs on half of the personal computers globally, will make way for later-generation products including Windows 10, a widely anticipated update that Microsoft pledged will contain many technological leaps.
But for most Chinese users, it will mean almost all the PCs, laptops and a small number of smartphones running without full original factory support, it said.
According to, an industry statistics site, nearly 57 percent of the Windows-based devices that are connected to the Internet in China are still running Windows XP, a system Microsoft stopped upgrading entirely last year.
With Windows 7, which holds another 38.3 percent of the market, being added to the products without support, 95 percent of the web-connected Windows devices in China will not get full technical support from Microsoft.
Local cyber security companies, including Qihoo 360 Technology Co Ltd and Beijing Rising Information Technology Co Ltd, have provided security updates for Windows XP users in China since Microsoft ditched the product.
Those companies have yet to announce if they will also patch Windows 7 after 2020, the report said.
Nicole Peng, research director at industry consultancy Canalys China, said most businesses in China still use Windows 7.
But piracy issues and the Chinese government's security concerns connected with the use of overseas software have made it difficult for Microsoft.
Regulators banned Windows 8 in government procurement deals in 2014 and are investigating if the company's Office software and Windows systems have violated the anti-trust laws.
Charlie Dai, principal consulting analyst at Forrester Research, said although the investigation could set back Microsoft's China business, local vendors will still find it difficult to edge into the market because software products from the US company are already tightly integrated into many business applications.