hi,anybody who can give detail guideline,as to which college or university is best for pakistani students interested in llm.

It depends what you mean by 'best'. You should consider what sort of LLM you want to do. Although most LLMs are taucht, it is possible to study for an LLM by research. Some institutions offer general LLM programmes, others provide programmes concentrating on specific areas of law. Equally, some institutions teach on a lecture-based model with exams, others base the LLM programme on seminars and tutorials and the assessment is in the form of research papers. All these factors will affect a decision about which institution is right for you.