The avenues from the airport are lined with the flags of the 16 participant countries, though the stars on the New Zealand flag are red, without the white outline.
Mr Wen and 22 officials lined up across the table from Mr Key. The New Zealand delegation included Trade Minister Tim Groser, foreign affairs officials and staff from his office.
Mr Wen invited Mr Key to China next year - but he will have retired by the time Mr Key gets there.
Mr Key said it would be about April - which would make him one of the first leaders to be welcomed by the new leadership.
The point Mr Key noted several times after the meeting was that Mr Wen said he wanted to see more New Zealand products being sold into China.
"You don't often hear that from such a large counterpart that they want to see more New Zealand products on their shelves and sold to their consumers," Mr Key said.
If New Zealand could have access to consumers around the world and sell its goods and services on fair terms, "then we can grow the wealth and affect jobs in New Zealand," he said.
"It's not much more complex than that."
A country of 4.5 million would never get rich selling to itself but selling to 1.4 billion Chinese would certainly help.
Mr Key said Mr Wen raised the issue of the disputed territory in the South China Sea and acknowledged New Zealand's position of not taking sides.
Mr Key and his entourage left Mr Wen's hotel to join Julia Gillard for a drink before heading to the gala dinner hosted by Cambodian Prime Minister Hun Sen. Mr Key was seated next to Mr Lee at the dinner.
Mr Obama arrived in Cambodia early evening local time after spending most of the day in Burma. He disembarked with Secretary of State Hilary Clinton.
It is the first time a sitting US President has visited either Burma or Cambodia.
The main item of business on the East Asia Summit agenda will be the launch of a new trade negotiation but Mr Obama is expected to also raise the issue of the conflict in Gaza.