if i want to travel from kunming to lijiang , what transportation will be better ? bus or train ?

Take bus. As I know the direct train from Kunming to Lijiang has stopped. Or you can take train from Kunming to Dali and then take bus from Dali to Lijiang. It takes 3.5-4 hours from Lijiang to Shangri-la. 5 days are enough. You can think of fly to LIjiang from Kunming.