"We are going to ask the audience on the road to turn their back when the Asian float arrives, and show banners. We have to send a strong message to say no to human rights abuses in China," Li said.

The float is sanctioned by the Beijing Olympic Organizing Committee but is sponsored by the Roundtable of Southern California Chinese-American Organizations and Pasadena-based label maker Avery Dennison Corp. It will feature the upcoming Olympics' five official mascots rotating on a base and decorated with a combination of flowers, including carnations and daisy petals.

Sheehan, the outspoken San Francisco Bay area activist whose son was killed in Iraq, is campaigning for Congress against Rep. Nancy Pelosi and calling for the impeachment of President Bush and Vice President Dick Cheney. She will join other pro-impeachment and anti-war groups at the parade, according to her sister, Dede Miller.

As many as 1,000 supporters are expected to rally before and after the parade and distribute 20,000 pamphlets while flying 300 banners along the parade route, said Peter Thottam, executive director of the Los Angeles National Impeachment Center.

Police said they were prepared for the protesters and the hundreds of thousands of spectators. As usual, about 1,200 officers from a number of agencies are set to be on hand.

"We've had to ramp up our resources, police personnel, but nothing out of the ordinary," police Commander Paul Gales said.