Hi， you can first fly to Changsha. Then take train or bus from Changsha to Chenzhou. You can take G-train from Changsha South Railway Station to Chenzhou West Railway Station. It takes about 65-80 minutes and it operates from 07:00 to 21:19. You can buy the train ticket at the railway station.
If you want to take bus ,you need to go to Changsha South Long-distance Bus Station. It departs at 12:50 and takes more than 3 hours. Thus, I advise you to take train.

Hi.my hometown is ChenZhou. so if your go to Chen Zhou by train,you have two choice,normal train and fast train. the fee of the normal train:52RMB,about 4hours.the fast train:160RMB,1 hour.if you go there by bus,about 4hours,138RMB.