Hi Srikanth,
Without knowing more about the technical environment you're going into, what level of understand they expect you to know, etc. it is hard to give guidance. What I would suggest is to drill down on some of the high level aspects of their environment if you know about them. For example, if they are a .NET environment versus a Java environment, you may want to ensure you understand what types of tools they are using for either and how they fit together. If they use a specific development methodology (e.g. RUP, Agile, Waterfall, etc.) look at overviews of these methodologies so you understand the basic terms and concepts. If they expect you to know UML, then look into that so you know the main concepts, diagrams, etc.
Hope this helps a little. Good luck!