You need to ride train and bus from Ocean park to Disneyland. They are far from each other, and it perhaps takes 1.5 hours or longer for the journey. Take bus 926 from Ocean Park to Admiralty. Get inside the MTR station and take Tsuen Wan Line to Lai King. Then change to Tung Chung Line to Sunny Bay. There is the special disney Line with cute train to the park directly.

Thank you Mr. Jameswong for the reply.
another question is, how to get back to TST if coming from Disneyland? in riding the Disney Train, is octopus card also accepted there? thanks for the reply sir...

This octopus card can be used for public transport (except mini-buses and taxis), thus it can be used for subway payment.

From Disneyland to TST:
Take the Dianeyland Resort Line to Sunnybay, change to Tung Chung Line to Central, Change to Tsuen Wan line to TST station.

To avoid a detour, the MTR route from Disneyland to Tsim Sha Tsiu is: Disney SPecial Line to Sunny Bay, Tung Chung Line to Lai King, then Tsuen Wan Line to Tsim Sha Tsui. Cost： 18.5HKD. 16.6HKD by using the card.