my arrival time at Harbin Airport is 11.00 pm. is it easy to get taxi to Songbei Shangri-La hotel ?

Yes, you can easily find several taxis outside the terminal building.

Or according to your arrival time, you can take airport shuttle bus line 1 and arrive at Tongda Street.
The bus will operate until the last flight arrival. After arriving, take a taxi to your hotel.

You can choose the way you like. :)