His remarks came as the world's two biggest economies are holding talks to resolve their trade war.
US negotiators are now in China for a week of talks ahead of the deadline at which point the USA would ramp up to 25 percent its tariffs on $200 billion of Chinese imports.
Investors will be looking to see if both sides can hammer out a deal before a March 1st deadline to avert higher US tariffs on Chinese goods.
The soft sentiment drivers for markets had circled President Donald Trump overnight with his lack of an outright objection to the border-security deal and the suggestion of his flexibility in the deadline for a trade deal with China.
As a result, some aides privately acknowledge the most likely scenario is for the March 1 deadline to be extended, and for tariffs on some $200 billion in Chinese imports not to be raised to 25 percent as Trump has threatened.
Mnuchin appeared at a Beijing hotel a couple of days ahead of scheduled high-level meetings with Chinese officials in the capital, with a March 1 deadline looming to strike an accord.
The South China Morning Post (SCMP) reports the latest comments from unnamed sources, as they cite that the Chinese President Xi Jinping will meet with the US Trade Representative Lighthizer and US Treasury Secretary Mnuchin on Friday. While those purchases will provide relief to USA farmers, there has been no breakthrough on the structural issues separating the two nations, such as industrial policy, government subsidies, protection of intellectual property or forced transfers of technology.
Trump said last week he did not plan to meet with Xi before the March 1 deadline. A round of talks at the end of January ended with some progress reported, but no deal and USA declarations that much more work was needed.
These include accusations of intellectual property theft and forcing American companies to share their technology with Chinese firms.
The talks kicked off in Beijing with discussions among deputy-level officials on Monday before minister-level meetings later in the week. According to a White House official, the delegates were preparing to focus more on pressing Beijing to gain a structural reform in China's business policy for the U.S. firms.