But those were different times, when the relationship was less interdependent, less vital to the global economy. Chinese government leaders know little about Mr. Romney, analysts here said, and view him as a new kind of Republican who is more conservative than those they have known.

In some respects, the Chinese government would probably prefer a continuation of the Obama administration, they added, on the basis that the incumbent is a known quantity.

“If Obama wins, we will have a smooth relationship without much change,” said Chu Shulong, a professor of political science and international relations at Tsinghua University in Beijing. “If Romney wins, there will be some uncertainty. If Romney wins, he has to keep some of his words.”

Of particular concern, Mr. Chu said, is Mr. Romney’s threat to name China a currency manipulator for keeping the renminbi at an artificially low level. But he and other analysts said they believed that Mr. Romney would be hard put to follow through. That is because the value of China’s currency against the dollar has risen substantially in recent years, making it less of a factor in providing Chinese exporters a competitive advantage, and because Mr. Romney would run into a wall of opposition from American businesses that fear they would be deeply scarred by any Chinese retaliation.

“Obviously people are not happy with the Romney rhetoric, but they assume he will adjust if he got into office,” said Dali L. Yang, a professor of political science at the University of Chicago and Tsinghua University in Beijing.

The American election and the impending leadership changes in China coincide with a growing confidence among the Chinese in their own strengths and more wariness toward the United States.

Just 39 percent of those polled in China during the Pew Research Center’s Global Attitudes Project earlier this year described the relationship with the United States as cooperative. In 2010, two-thirds of those polled called the relationship cooperative. Only 8 percent saw the relationship as hostile in the 2010; this year 26 percent viewed it that way.