The US star, speaking at the Cannes Film Festival, linked the recent disaster to Beijing's policy on Tibet.
She said: "I thought, 'Is that karma?' When you are not nice, bad things happen to you."
But Stone added she "cried" after the Tibetan Foundation asked her to help quake victims.
Stone, 50, said: "They wanted to go and be helpful, and that made me cry.
"It was a big lesson to me that sometimes you have to learn to put yourhead down and be of service even to people who aren't nice to you."
Stone made her comments last week in a brief interview with a Hong Kong film crew.
"I'm not happy about the way the Chinese are treating theTibetans because I don't think anyone should be unkind to anyone else,"Stone said in footage widely available on the internet.
"And then all this earthquake and all this stuff happened, and I thought, is that karma?"