via subway, from hongqiao airport to kunshan?

You have to detour to travel by subway. Anyway, here is the way: take subway line 2 to Jiangsu Road, and transfer to line 11 to Huaqiao. Then you need to transfer to bus or taxi to Kunshan downtown.

Another way is to walk from SHA to Hongqiao Railway Station in 10-15min. There you can take a train to Kunshan South in around 20min. Afterwards, you still need to transfer to the downtown area.