Chinese President Xi Jinping is exploring new territory during what he has called a "pioneering" trip to Saudi Arabia. He has signed dozens of deals to "usher in a new era" in relations with the Arab world.
Xi was welcomed on Thursday to the royal palace in Riyadh by Crown Prince Mohammed bin Salman.
China has become Saudi Arabia's largest trading partner, while the kingdom is one of China's largest suppliers of oil.
Xi said that under King Salman and the Crown Prince's leadership, the people of Saudi Arabia will keep striving to "blaze a path of modernization" suited to their national conditions and to realize even greater achievements.
Chinese companies are already invested in megaprojects across Saudi Arabia, including railways, hydrogen plants and the infrastructure for fifth-generation cellular networks. Xi wants to export even more technology.
Saudi state media say Xi and King Salman signed a "comprehensive strategic partnership" and have pledged to exchange visits every two years.
The Saudis have spent decades fostering security and economic ties with the US. However, President Joe Biden has accused them of siding with Russian leaders to cut oil production. He has said he is "rethinking" the relationship.