La-Zarar(No-Harm) as a Theory in the Structure of Islamic law

La-zarar(no-harm) is one of the important rules governing the system of family law in islam. Islamic jurists(foqaha) have expressed different views on narratives about la-zarar and how to use it in inferring legal rules in the Islamic legal system in general and family law system in particular.Despite the importance of discussions conducted about these narratives this paper will attempt to reinvestigate these topics in the form of a theory (harm negation and prevention theory). Here we first define the theory domains and levels of the Islamic legal system. Then through a systematic look, the position of harm negation and prevention is considered.