Xi, making his first presidential visit to the Middle East, will also travel to Egypt and Iran.
The official Saudi Press Agency confirmed his arrival.
Tensions between regional powerhouses Saudi Arabia and Iran reached a new high this month when Riyadh and a number of its Sunni Arab allies cut diplomatic ties with Tehran.
The schism came after protesters burned Saudi diplomatic missions in Iran following the kingdom's January 2 execution of Shiite cleric Nimr al-Nimr.
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Xi also arrives three days after a historic international deal lifted sanctions on Iran in return for a scaling back of its nuclear capabilities.
China and five other world powers helped broker that agreement. But Riyadh fears it will further embolden Iran, which it accuses of regional interference.
Last week a Chinese diplomat urged "calm and restraint" between Saudi Arabia and Iran, but Xi's trip was most probably organised before the discord, Zhu Feng, professor at Peking University's School of International Studies, told AFP before the visit.
"China will try and do what it can, but it still won't play a main role."
In the past month, Beijing has hosted high-level members from both the Syrian regime and its opposition.
China has consistently urged a "political solution" to the Syrian war, despite being seen as sympathetic to President Bashar al-Assad after vetoing UN Security Council measures aimed at addressing the conflict on four occasions.
Iran is one of Assad's main allies while Saudi Arabia backs rebel forces, and in December hosted an unprecedented meeting of the Syrian opposition.