Xi has spoken to Putin several times since the war began, but has not done so with his Ukrainian counterpart Volodymyr Zelenskyy.
Lukashenko is a close ally of Putin and has backed Moscow’s invasion of Ukraine.
Belarus shares a border with both Ukraine and Russia, but is financially and politically dependent on the Putin administration.
A year after allowing Russia to use Belarus as a launch pad for its Ukraine offensive, Lukashenko said that he was ready to do so again if Minsk felt threatened.
Kyiv has also expressed concerns that Belarus could again support Moscow in its war effort.
In September last year, Xi and Lukashenko met in the Uzbek city of Samarkand, where they again hailed their “all-weather” partnership.
Lukashenko’s Beijing visit follows the announcement on Monday that the European Union had extended by one year sanctions on Belarus over Minsk’s repression of political opposition and its support for Russia’s war.
The bloc has hit Belarus with multiple waves of sanctions since Lukashenko launched a brutal campaign of repression against demonstrators protesting a disputed election in 2020.
The sanctions have been extended until February next year, the European Council, which represents 27 EU member states, said in a statement.