I am staying at the Ibis in Harbin near Zhaolin park

You can walk to the Central Avenue Station first. There is shuttle bus line 3 that can take you to the airport directly. The pick-up station is located at no.59, Second Jingwei Road.
The earliest schedule is 05:50 am with the interval of 40 mins. It will take around 50 mins on the way. :-)