In February, more than 221 million people in China used the Internet, the report states.
While that was enough to topple the U.S. total, the penetration rate in relation to the Chinese population is still lower than the worldwide average, Reuters reported. Sixteen percent of China's population uses the Internet, compared with 19.1 percent on a global scale, the report notes.
But not all figures agree with the China Internet Network Information Center's findings, Reuters noted.
Market research company ComScore reported that the U.S. still had more Internet users than China did at least through March. ComScore said the U.S. had 188 million Internet users last month, compared to 173 million in China.
ComScore representatives told Reuters the discrepancy could be because the company collects data on a monthly basis, while the China Internet Network Information Center collects data over six-month periods.
In January, the China Internet Network Information Center said China's total number of Internet users rose 53 percent to 210 million at the end of 2007, up from 137 million at the end of 2006 and 162 million in June 2007.
At the time, the Wall Street Journal reported that China was just 5 million users shy of surpassing the United States as the world's largest Internet market.