Annan, who was met by Foreign Minister Khurshid Kasuri, is due on Friday to tour parts of northern Pakistan hit by the October 8 earthquake that killed more than 73,000 people and made about three million homeless.
On Saturday he will attend a donors' conference to raise money for the massive reconstruction effort.
Pakistan will need about 5.2 billion dollars to recover from the quake, according to a figure compiled by UN and Pakistan agencies, the World Bank and the Asian Development Bank.