MOFCOM's decision was the last regulatory approval required for the merger and the two companies expect to combine operations on 23 September, Marriott said.
Marriott won the right to buy Starwood after a bidding war with a Chinese consortium led by Anbang Insurance Group.
The companies have had to wait for the Chinese approval since August, when MOFCOM requested more time to complete its review. They had already received unconditional premerger clearances from regulatory authorities representing over 40 countries worldwide, including the United States, the European Union, Canada, Chile, Colombia, India, Japan, Mexico, Pakistan, Saudi Arabia, South Africa, South Korea, and Turkey.
The European Union gave approval in June.
US-based Marriott has more than 4,500 properties in 88 countries, while Starwood has over 1,300 properties across 100 countries, Marriott said.
Starwood shares will cease trading on the New York Stock Exchange on 23 September, Marriott said. Starwood shareholders will receive $21 in cash and 0.80 share of Marriott Class A common stock for each share of Starwood common stock.