He's the most senior Chinese official to visit the US since President Donald Trump took office and his two-day trip comes as tensions bristle with North Korea and its neighbors.
"My speculation is that Yang will try and persuade the US government to be open to talks," said Tong Zhao, an associate at the Carnegie Tsinghua Center for Global Policy.
Beijing, North Korea's only real ally and economic benefactor, has long advocated diplomatic talks but Washington has stayed focused on sanctions, with Trump repeatedly saying China isn't doing enough to rein in its unruly neighbor.
But Yang's trip comes after a potential change in dynamics.
Coal is North Korea's main export and an important source of foreign currencies for its fragile economy.
China's move will test whether Trump really is willing to do something about North Korea's nukes -- the President has vowed to deal with North Korea and his administration is conducting a policy review.
Engagement?
However, North Korea's most recent provocations make any kind of US outreach difficult.
And just when it seemed nothing could make North Korea's international standing any worse, it assassinated the estranged older brother of leader Kim Jong Un, Kim Jong Nam, at Kuala Lumpur airport, on February 13.
Even though the government wouldn't have taken part, the talks could have signaled that the new administration was more open to US engagement with North Korea, said Zhao.
"There was hope in China that the talks would happen," he said.
China's beef with North Korea
Beijing has backed Pyongyang since the two fought together in the Korean War.
The murder of the Kim Jong Nam, who was living in China and advocated Chinese-style economic reforms, is likely to have further soured ties.
But while China may be fed up with North Korea, that doesn't mean China is ready -- or able -- to rein in its unruly neighbor or coax it to the negotiating table on terms the US would approve of.
Beijing is opposed to any scenario where the regime topples -- leading to a massive influx of refugees and potentially US troops on China's doorstep.
Anthony Ruggiero, a senior fellow at the Foundation for Defense of Democracies (FDD) is also skeptical that China's coal ban is really that and says that China could still do more damage to its neighbor.
"US and Chinese priorities do not match up on North Korea," he said. "And I haven't seen anything that suggests China is taking a different approach."