"On the afternoon of the 14th, Cambodian Prime Minister Hun Manet arrived at Beijing Capital International Airport to begin his official visit to China," state broadcaster CGTN said on social media platform Weibo.
"This is the first official visit of Prime Minister Hun Manet since he took office," it added, noting "the 65th anniversary of the establishment of diplomatic relations between China and Cambodia" this year.
Hun is expected to pay a courtesy visit to Xi, as well as hold talks with Premier Li Qiang and Zhao Leji, head of the Standing Committee of China's top lawmaking body, his spokesperson Meas Sophorn told the press at Phnom Penh International Airport.
He will then travel to the southern city of Nanning to attend the 20th ASEAN-China Expo.
Phnom Penh became one of China's strongest allies in the region under Hun Sen, who ruled with an iron fist for almost four decades, receiving huge sums of Chinese investment.
The visit will be one of Hun Manet's first abroad since becoming prime minister, after he attended the summit of ASEAN leaders in Jakarta last week.