Is there airport transfer to Hongkong from Baiyun Airport?

No, there is no such transfer. For this journey, it is suggested to take airport shuttle bus line 6 to local East Railway Station, where there are direct trains to Hung Hom, HK. Then you can take HK bus or MTR to your destination at Kowloon. For the back journey, you can use the same way. And the shuttle bus fare is CNY20 per person and the train ticket costs CNY190HKD per person for single journey.