Beijing's economic growth rate lagged behind the national average during the first three quarters, according a municipal statistics bureau report on Wednesday.
The city registered a total output value of 758.63 billion yuan (111.13 billion U.S. dollars) in the first nine months, up 9.1 percent from the same period last year, but below the national average of 9.9 percent.
The report said secondary, or manufacturing, sector was up by 4.1 percent and the tertiary sector rose by 11.1 percent in that period. The service sector made up 70 percent of the city's economy.
Bureau spokeswoman Yu Xiuqin said the slowing economic growth could not be attributed to a "post-Olympic" downturn.
"Preparations for the Olympics greatly improved Beijing's infrastructure. The Games helped the city's economy in the long run," Yu said.
Beijing faced a very complicated economic situation this year, she said.
Central government measures to rein in real estate investment have taken effect, while the sluggish international market and flagging investor confidence also attributed to the slow down.