The "volunteers" from "all walks of life" have been trained and will be sent to "every street, every alley" as well as stores and markets, the official Xinhua news agency said late Wednesday, citing a Beijing police spokesman.
They will look for signs of "security hazards" and report them to police, it added.
The Chinese government often uses huge amounts of manpower to strengthen security during major events, such as the 2008 Beijing Olympics and the following year's 60th anniversary of the founding of Communist China in 1949.
Communist China generally shies away from the vast annual demonstrations of military might that were a hallmark of the Soviet Union, normally holding such events once a decade to mark the foundation of the People's Republic.
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But Beijing is becoming increasingly assertive in the region and regularly accuses Tokyo of failing to show sufficient contrition for Japan's 20th-century invasion of China.
The centrepiece of the parade route is through Tiananmen Square, the symbolic heart of the Chinese state, and the Tiananmen rostrum on the north side of the plaza has been shut to tourists since the start of this month.
Curfews will be imposed in Tiananmen Square and the nearby Wangfujing shopping centre during rehearsals this weekend and for the actual parade, state media reported previously.