This study focuses on the application of the instrument al-Istihsan bi al-'Urji in justification of "harta sepencarian " practice. Basically, this instrument motion derived from the Hanafi school. But technically, it is not dissimilar to the instrument 'urfi according to Shafi 'i school. Furthermore, the concept of "harta sepencarian" division is practiced in the Malay community, especially in Nusantara, which is the majority, upholds the Shafi'i school. This study uses library research methodology with reference to the writings of scholars in the Hanafi and Shafi 5' school in order to justify the acceptance of the practice of "harta sepencarian" in Shari'ah law This study tries to find justification in the other school in an attempt to develop a practice that benefits and defense women, particularly to Muslim countries other than the Muslim community of the Nusantara.