Hi, how do i go grand mercure Oriental ginza hotel from Shenzhen shekou ferry terminal

You can take the subway Shekou line from the port and get off at Window of the World. Then transfer to Luobao Line and get off at Zhuzilin Station. Walk about 250 meters to the destination.

So its ensure the ferry terminal just besides the subway stn. Is there any alternate mode of transport to hotel and how long would the distance take and fare charge?

Yes, the metro station is within walking distance to the Shekou Port. Apart from the metro, you can also consider taking a direct bus or taxi to reach. This hotel is 9-10mi away.
By bus: take bus no. 329 at the port and get off at Zhuzilin stop. After that, u can walk to ur destination within 535yd.