hi how can I go to Hong Kong Disneyland from L'hotel island south .

Walk to the Yip Hing Street, Wong Chuk Hang Road to take the bus 170 and get off at the Tai Wai Railway Station. Then transfer to bus R42 and get off the Disneyland Bus Terminus. Walk to your destination.

Joe's way will work, but as I know, it takes around 120min to arrive. I know a way by bus + MTR, taking around 80min:
walk from the hotel to Yip Hing Street, Wong Chuk Hang Road to take bus no. 72A to get off at Sogo Department Store, Hennessy Road. Then you can walk to Causeway Bay MTR station to take Island line to Central. Then follow the clear guiding signs to HK Station to take Tung Chung line to Sunny Bay, where transfer to Disneyland Resort line to the park.