If i am travelling to mutianyu great wall from airport, can the tourist service center help me?

The tourist service won't help you with the transportation and there is no direct transportation or special pick-up service. You need to hire a private car by yourself or just take the public transportation. Take Airport Express to Dongzhimen Station, Exit E first. Then, you can take bus line 916 Express. Transfer to bus line h23, h24, h35, or h36 to Mutianyu Roundabout. Afterwards, walk about 500 yards (450 meters) to the ticket office of the scenic area.

Well, as I know, the tourists center doesn't provide the luggage storage service. Thus you are advised to put your luggage at the airport or the booked hotel in downtown area.