Animal activists were led away by police after running down the track during the Epsom Derby as the Princess Royal and her family looked on.
Pro-vegan climate group Animal Rebellion claimed six women entered the area wearing scarves reading “Animal Justice” just before the Cazoo Derby at 4.30pm.
It comes after activists from the same group entered the ceremonial route on The Mall ahead of Trooping the Colour, later arrested by police on Thursday.
The women could be seen falling to the ground when police came to them on Saturday.
Dozens of officers worked to move them, as members of the royal lodge watched.
The Queen’s daughter Anne was there alongside her husband, Vice Admiral Sir Tim Laurence, and children Peter Phillips and Zara Tindall, who was with her husband, former rugby player Mike.
The crowd cheered as the activists were led away, with a voice over a Tannoy apologizing to the onlookers.
The group said the protest was intended to make “a definitive statement and take action against the cruelty and damage that the horse racing industry represents”.
One of them, Orla Coghlan, said: “Horse racing claimed the lives of 220 animals at UK racecourses last year, and that’s just the tip of the iceberg. .
“In this country, more than a billion land animals are killed each year for food. Exploitation and violence against animals is fueling the climate emergency and suffering across the world.
“It is obvious that we must choose life over death and stop animal exploitation.”
A spokesperson for the group said: “Whether it’s horse racing, dairy or the meat industry, animal exploitation has no place in our world.”
Surrey Police have been approached for comment.