How can I go to Huangshan from Nanxun water town?

Well, I cannot find the direct bus that operates between these two places.
You are advised to take a coach from Nanxun Ancient Town to Jiaxing first. Then take a taxi to Jiaxing South Railway Station. Take bullet train to Quzhou Railway Station and transfer to bullet train to North Huangshan Railway Station.
After arriving, transfer to a tour bus in the front square of the station to the transfer center of Mount Huang. The tour buses depart from 08:00 to 20:20. You can also hail a taxi from the railway station to the scenic area, and it would cost around CNY 160.