How to get from Kunming Railway Station to Wuhua District Nanping Pedestrian Street?

You can take public bus no.68, and get off at East Gate of Nanping Street. Then walk southwest around 250 yards to find the destination.
If by cab, it would cost around CNY 11 in the day time.

How many pedestrian street and old town are there to visit?
How to get there if I am staying at Dazhen Hotel (Previously: Qian Lv Chen Hotel Da Zhen) 8th Floor, Da Zhen Plaza, 408 Beijing Road Panlong or
City Star Ji Feng Branch No.636 Beijing Road,Pan Long District, Panlong, 650051, China

Apart from Nanping Street, you can also go shopping at Zhengyi Road. As for the old town, the Guandu Ancient Town is high recommended.

From Dazhen Hotel to Zhengyi Road: walk west for about 100 yards to Tangzi Lane (Tuodong Road), and take bus line 1 to Confucious Temple (Wen Miao) Station. Then, you can see it.

From Dazhen Hotel to Guandu Ancient Town: take bus line 161 from Desheng Bridge (Qingnian Road) Station to Wu Jia He Station. Then, change to bus line 186, C142, or 165 to it.

From City Star Ji Feng Branch to Zhengyi Road: take bus line 61 from Fenghuang Village to Confucious Temple (Wen Miao) Station.

From City Star Ji Feng Branch to Guandu Ancient Town: walk north for about 500 yards to Chuanxin Gulou Station. Next, take metro line 2 to South Huancheng Road. Then, take bus line c85 to it.

how if go by subway

There is no direct subway service between them. It will be much convenient for you to take a bus. :)