Guinness adjudicator Dong Cheng said the volunteers gathered in Shanghai to beat the record of 850, which was set in February in New Orleans.
Cheng said the human mattress dominoes took 11 minutes and 11 seconds to fall.
"For an event like this involving 1,000 people, to succeed [the] first time is not just about luck. All other conditions must be correct. First of all, all the participants must fully understand the rules," Cheng said. "Second, the volunteers were all very brave. No one dodged when the 2-meter-high [about 6 feet-high] mattress fell onto them."