may i know the distance from Guangzhou airport to the 12 districts of the city separately.

Firstly, I'd tell you that there are 11 districts in the city now according to the latest news in 2014. Well, here is the general info for your reference:
To Yuexiu District: around 31km
To Liwan District: around 35km
To Haizhu District: around 45km
To Tianhe District: around 44km
To Baiyun District: around 29km
To Huangpu District: around 50km
To Panyu District: 65-67km
To Huadu District: 20-21km
To Nansha District: around 100km
To Conghua: around 56km
To Zengcheng: around 78km