hello , how can i get to Dunhuang from Guangzhou by train or coach ,any suggestion ? many thanks

Here are some ways that you can choose.
1. by train:
take the high speed train at Guangzhou South Railway Station to Lanzhou West Railway Station. Then transfer from Lanzhou West Railway Station to Lanzhou Railway Station. Then take the normal train to the destination.

Or take the bullet train to Xian North Railway Station and then take the normal train at Xi'an Railway Station.

2. By air: make a transfer in Lanzhou airport or Xi'an airport to DH airport

3. Air + Train: Fly to Lanzhou airport or Xi'an airport and then change to take the train to there.