In a video posted Thursday on social media, Maduro said, "Where we're heading is for the Moon, to a splendid era for China and Venezuela".
He said the two countries "have declared the relationship as an airtight and strategic partnership for all times".
And speaking at a press conference Thursday as he wrapped up the trip, Maduro said China and Venezuela had entered "a splendid stage in economic, cultural, educational, civilizational, scientific achievements".
"We had never achieved a document of the depth, strategic importance and consensus of this document," Maduro said.
He also showed off two gifts from Xi, including a Huawei folding mobile phone.
"It is the most secure phone, impossible to break into," he said.
The two sides said in an agreement signed on Wednesday they "are close friends of mutual trust, good partners of common development, and dear partners of strategic collaboration".
It also reiterated Venezuela's interest in joining the BRICS group of major emerging economies that held its most recent summit in August in Johannesburg.
The original grouping of Brazil, Russia, India, China and South Africa announced at that summit its admission of six new countries, including Argentina.
Venezuela "can contribute significant strengths to the group's energy agenda, as a reliable supplier and the country with the largest proven oil reserves and the fourth-largest natural gas reserve worldwide", Wednesday's agreement said.
China maintains close relations with the internationally isolated but oil-rich Maduro government and is one of Venezuela's main creditors.
The South American country's GDP fell 80 percent in a decade due to the effect of its economic crisis, with citizens struggling to access basic necessities and millions having fled the country.
© 2023 AFP