Which bus should I take to Qingdao Sifang Bus Station to go to Huanghai Hotel?

Are you talking about Huanghai Hotel or Huanghai Hotel?

The former seems to be in Yangkou, while the latter is near the bathing beach.

If it is the Yellow Sea Hotel, you can take 15 from Sifang or Lijin Road Long-distance Station to Xiaoxihu directly.

Sifang Railway Station-Long-distance Station (Inner Mongolia Road)-No.34 Middle School-Cao Xian Road-Weihai Road-Taitung (Beer Street)-No.15 Middle School-Zoo [West Gate]-Xiaoxihu Lake

Get off at Sifang Railway Station and get on at Lijin Road Station to Cao Xian County.