Landing in HONGKONG then taking a train to Guangzhou

The trains depart from Hung Hom Railway Station to Guangzhou. From HK airport, you can take bus A21 to get to the railway station directly. Duration is abut 1.5 hours and bus fare is HKD33.

Thank you , what is cheaper- the train or bus. Which one takes longer ?

By mentioning bus, you may refer to the direct cross-border coaches from HKIA to Guangzhou, right? It takes around 4h and the bus fare is 250HKD.

While by train, transfer is needed just as Lucas said, but it takes less. Considering vehicle waiting time and passing immigration duration, around 3h is needed. The cost is 33HKD + 190HKD = 223HKD.