Xi hosted Lukashenko at the ornate Diaoyutai state guesthouse, Chinese state broadcaster CCTV said.
"China-Belarus relations have withstood the tests of international challenges" and are "entering the best period in history", a Chinese government readout said.
Xi told Lukashenko their two countries "should mobilise resources in all areas to promote the construction of the Belt and Road Initiative and enrich the content of practical cooperation", according to the readout.
The Belarusian leader's visit comes after he met with Russian President Vladimir Putin last week.
Lukashenko, who has been in power since 1994, allowed Moscow to launch its 2022 Ukraine invasion through Belarus but has denied plans for direct involvement in the war.
Belarus, which borders NATO's eastern flank, hosts Russia's latest nuclear-capable missile, the Oreshnik.
China has presented itself as a neutral party throughout the conflict, although Kyiv's allies have long accused Beijing of secretly helping Moscow.
Lukashenko last met Xi in August 2025, before attending a grand military parade in Beijing days later.