Hi, I am planning to Hong Kong on 22-29 Mar2014, how the itinerary should in plan and weather ?

Oh, you would have a long term trip. If you don't mind, I suggest you spend three to four days in HK and for the rest days, you may spend in Macau and Shenzhen, both of which are easily reached. In HK, Disneyland Resort, Ngong Ping 360/ Giant Buddha, Ocean Park, the Peak, Victoria Bay, Avenue of Stars and TST cannot be missed.

In Macau, you can visit the Venetian Resort, Fisherman Wharf, Senado Square, Ruins of St. Pauls and City of Dreams. In Shenzhen, Window of the World, Splendid China and Folk Cultural Village, Dameisha/Xiaomeisha and OCT East as well as Dongmen Pedestrian are worth destinations.

During that time, it will be warm in HK, with the average temp of around 22C. At the same time, you may meet several rainy days.
Hope help!