Wei Fumin, a zoologist at the Chinese Academy of Sciences and a member of the research team, said the researchers believed that as many as 72 pandas may be living in the Wanglang Nature Reserve - more than twice the previous estimate of 32.
The team took samples of panda droppings in the reserve and developed genetic profiles to draw the conclusions, Wei said.
The rising numbers are probably the result of natural population growth, migration from other areas and the effectiveness of conservation policies such as a logging ban to preserve panda habitat.
"We're really seeing these policies start to have an effect," Wei said.
The research was conducted by a joint British-Chinese team and published on June 20 in Current Biology.
Despite the rising numbers in Wanglang, Wei said it was too early to say whether similar studies in other preserves would show a higher overall number for China's wild panda population, now estimated at about 1,600.
"There could be other factors at work in different places," he said.
Another of the study's authors, Michael Bruford of Cardiff University in Wales, said the environment at Wanglang was not significantly different from that at China's other 40 panda sanctuaries, implying there could be many more pandas than believed.
And while conservation programmes were clearly working, the degree of genetic diversity uncovered at Wanglang seems to indicate that panda numbers never fell as low as previously thought, Bruford said.
The authors said they do not expect the findings to dampen China's enthusiasm for assisted breeding, which has proven effective in boosting numbers of captive pandas.
Bruford said a separate Chinese team had developed the DNA testing method, testifying to Chinese scientists' rising prominence in the field of genetics.
Wei said the new methodology also sheds light on little-known aspects of panda life, such as family ties, geographic dispersal, age distribution, mating and migration habits.
Samples taken at Wanglang showed considerable genetic diversity among the panda population, implying robust numbers and considerable migration in and out of the 320km preserve high in the mountains of Sichuan province in southwestern China.
"Pandas are very hard to study and there's a lot to be known other than just their population," he said.