void thread1(){
    boost::mutex::scoped_lock lock(mutex);

...//do some work
    data_ready=true;
    cond.notify_one() //assume the condition is satisfied.
     //do more work    -------my question is will this part continue? or thread2 will wake up and block thread 1?

}

The thread1() will continue and the thread2() will be still locked. If you wish to avoid this situation, you have to unlock the mutex manually before the notification:

lock.unlock();

cond.notify_one();

...as explained here:

http://www.justsoftwaresolutions.co.uk/threading/implementing-a-thread-safe-queue-using-condition-variables.html