Thousands of believers, many from neighbouring countries, are expected to pour into CAR's capital Bangui to see the 78-year-old pontiff on his landmark visit to one of Africa's poorest and most unstable countries.
As he stepped off the plane, he was greeted by acting CAR president Catherine Samba-Panza under tight security with roads leading to the airport bristling with troops and security forces, an AFP correspondent said.
His plane touched down at around 10:00 am (0900 GMT) at Bangui airport close to an area where tens of thousands of displaced people have sought refuge from sectarian clashes since 2013.
UN peacekeepers and French troops are based in the airport area.
Ahead of the visit, workers have been busily repairing potholes and sprucing up Bangui's cathedral square for the visit which many are hoping will bring hope to a country where violence has raged for more than two years.
Stalls have sprung up across the capital selling everything from Vatican flags to paper crowns to welcome the pope.