President Xi Jinping also pledged with his South Korean counterpart Park Geun-hye, to work towards wrapping up a free trade agreement by the end of the year.
It's President Xi's fifth meeting with the South Korean leader since both leaders took office last year.
So is it significant that President Xi visited Seoul and not Pyongyang?
Presenter: Sen Lam
Speaker: Taylor Fravel, Associate Professor of Political Science and member, Security Studies programme, MIT, Cambridge, Massachussetts
FRAVEL: Yes, in fact this is perhaps one of the most significant aspects of President Xi's trip after South Korea. Typically, Chinese leaders will visit North Korea before they visit South Korea, and in this instance, Xi has done the reverse. He has no plan to visit North Korea, nor has he invited the North Korean leader to visit China.
LAM: So, of course, this is against the backdrop of Japan this week, revising its pacifist Constitution. Do you think South Korea and China might be looking to each other for support to counter the new mood that's current in Japan, under Shinzo Abe?
FRAVEL: I think they might be looking for moral support or rhetorical support, but I don't think South Korea is looking for closer military cooperation with China, that's not what South Korea wants.
But certainly, South Korean-Japanese relations have reached a new low under President Park and the domestic politics in both countries have prevented the leaders from meeting. So what's remarkable about President Xi's trip is that the South Korean leader is meeting with, is having a formal statement with the Chinese leader, before she has one with the Japanese leader.
LAM: Well, President Xi agreed with his South Korean counterpart, Park Geun-hye, that the de-nuclearisation of North Korea must be realised by all means. But I understand that Beijing and Seoul differ on the method in which they could do it?
FRAVEL: Yes, so to date, China has not made a de-nuclearisation, its top priority on the Peninsula. It's top priority until recently has been maintaining the domestic, political stability of the government in North Korea and not taking actions on the nuclear programme that would create domestic instability, which China, I think views as putting a more direct and immediate threat, than North Korea's possession of nuclear weapons.
LAM: The Chinese leader, of course, was also accompanied by a huge business entourage. How do you see that business relationship progressing in the coming years?
FRAVEL: I think the economic relationship between the two countries is only going to deepen further in the next five to ten years.
Geographically, they're quite close to each other, their economies are complimentary, in many ways. South Korea has advanced technologies that China would like to incorporate into its own economy.
South Korean companies have invested very heavily in China, especially in northern parts of China and both countries, I think see that deepening the economical relationship will be mutually beneficial.
LAM: And where North Korea is concerned, what do you think Seoul is seeking from Beijing?
FRAVEL: I think Seoul would like Beijing to place more pressure on North Korea, to restrain North Korea from conducting armed provocations across the North Korean-South Korean border.
You might recall back in 2010, South Korean naval ships were sunk off the coast of South Korea. Shortly thereafter, in the same year, North Korea shelled an island that is held by South Korea, killing two soldiers and two civilians.
And so South Korea are quite worried about political stability in North Korea and the possibility that violence might escalate with its northern neighbour. China could certainly help to restrain North Korea in that way, as well as helping to bring about ultimate de-nuclearisation on the peninsula.