How can I go to North Bus Station from Kunming Railway Station by bus?

You can take public bus no.23, get off at North Public Transit Hub. Then walk south around 100 yards to arrive at the North Bus Station. Generally speaking, it takes around an hour on the way. The ticket fare is CNY 2 per person.
If by taxi, it costs CNY 40 to 50 in the day time. And the duration is about 20 mins.