Ya'an is located at the western edge of the Sichuan Basin and on the upper reaches of the Yangtze, covering the transition between the Chengdu Plain and the Tibetan Plateau. With an area of 15,300 square kilometres (5,910 sq metre) and a population of 1,530,000, the city is encircled by mountains, and four rivers flow through it. Ya'an is 130 kilometers (81 miles) from Chengdu and only fifty minutes' drive from the Chengdu Shuangliu International Airport. It links central Sichuan to the three ethnic minority prefectures (Garze, Aba and Liangshan).

The city lies in the subtropical climatic zone where humid, monsoon-like conditions can exist.  The weather in northern and southern DaXiang Ling varies greatly and the climate differs as the terrain changes. Its annual average temperature is around 16℃ (60.8℉).    Ya'an is truly a rain city. There is rain 180 days of a year. Despite the humid conditions, the city is still a year-round tourist destination. However, it is a good idea to be cautious during the rainy season in summer, as accidents caused by floods can occur.

In 1868, a French missionary first discovered the giant pandas in Ya'an. Today the area is home to the Fengtongzhai Nature Reserve and Chinese Giant Panda Preserving Base of Bifengxia Station. Both were built here for scientific research and panda breeding.