I've already created my internal automate framework which use for unix application testing , so I need to apply keyword driven testing into it. But one of my concern is this won't work with complex scripting have you ever face this problem?
Hmmm... I still don't understand the question really. If you implement a keword driver/framework and you have other users creating functions for the test automation you will have to coordinate that. The keyword frameworks I've worked with usually have more complex code in the driver than in the keyword functions.
Ukarick, I think you are saying in a keyword driven approach, it is not feasible for all keywords to be scripted and there is some automation that generally has to be scripted outside of keywords.
That is true, unless you are building an automation framework that encompasses keywords for all possible automation steps.