Li, the prime minister of the world's second largest economy, said after a summit with EU leaders that it was a "critical" moment in the standoff between Greece and its EU-IMF creditors.
"China wants to see Greece stay in the eurozone and we urge relevant creditors to reach agreement with the Greek government at an a early time," Li told a news conference.
Speaking alongside EU President Donald Tusk and European Commission chief Jean-Claude Juncker, Li added that China wanted "progress... So both Greece and Europe overcome the current challenges and crisis."
"Several times China has taken real actions to respond to the concern and requests from the Greek government, because we hope that Greece would do well and hope to see a united European Union," he said.
Greek Prime Minister Alexis Tsipras has called a referendum yesterday on whether Greece should accept reform plans under an international bailout.
EU ministers decided Saturday not to extend the bailout because of the lack of a deal, meaning Greece is set to default on a IMF loan repayment on Tuesday.