Biden, who left Chengdu, capital of southwest China's Sichuan province, would travel to Mongolia before visiting Japan to complete his Asian tour, his first as U.S. vice president.
During his stay in China, Biden met with top leaders, including President Hu Jintao, Premier Wen Jiabao and Vice President Xi Jinping, the likely successor to Hu. Xi accompanied him to Sichuan.
Throughout his trip, the official Chinese media has been reminding that China, America's largest foreign creditor, held $1.16 trillion of U.S. treasurys as of June.
Biden's visit came in the midst of the global financial turmoil triggered by the Aug. 5 downgrade of U.S. debt by Standard & Poor's, raising Chinese concerns about the safety of dollar assets. Other credit rating agencies, however, have retained the United States' triple-A rating.
In a speech Sunday at the Sichuan University, Biden, answering a question, noted the downgrade by the rating agency, but said the United States remains the "single best bet in the world in terms of where to invest," the Los Angeles Times reported. He said the deficit would be dealt with by his government.
"So our interest is not just to protect Chinese investment. We have an overarching interest in protecting the investment, while the U.S. has never defaulted and never will default," the Chinese media quoted him as saying.
"We are still the single best bet in the world in terms of where to invest. You're safe," he added, while noting a more prosperous China will mean more demand for American-made goods and services.
At their weekend meeting, Chinese President Hu Jintao told Biden his visit would "also help push forward exchanges and cooperation between our two countries in various fields and make new contribution to the building of a China-U.S. cooperative partnership."
Biden said U.S. President Barack Obama had asked him to come to Beijing to "reaffirm our absolute, total commitment to a strong and enduring positive relationship with China, and to reaffirm our commitment to stay engaged in the world in the most vigorous way possible."
Biden and Xi took in some basketball Sunday during a visit to a school outside Chengdu, the White House said.
The school, which was rebuilt after a 2008 earthquake, includes a basketball court donated by the National Basketball Association, and Biden and Xi obliged the media by taking a few shots.
Biden joked about suffering jet lag after putting up what the White House said in a written statement were two air balls, a "brick" and one that went wide left.
The kids at the school didn't seem disappointed. They politely applauded the errant shots and said goodbye to the party in English.