Background and Aim: The harmless rule is comprehensiveness and dynamism in the Islamic legal system and has an undeniable effect on Iranian civil laws and has been able to solve many problems and even emerging issues. The objective of this study is to analyze the "Harmless jurisprudential rule" with the investigation the effect of the sale of building density on the environment and individuals of the society.
Materials and Methods: This research is of theoretical type and descriptive-analytical and library and has been done by referring to documents, books and articles.
Ethical Considerations: In order to organize, while observing the authenticity of the texts, honesty and fidelity have been observed.
Findings: offering surplus density and selling building density In cities, especially metropolitan areas, which can be studied according to the consequences which have for the environment, society and individuals. by adopting appropriate mechanisms in the field of environmental protection and sustainable urban planning, jurisprudential and Islamic rules can be used to organize this area, and this important issue can be examined in the form of a harmless jurisprudential rule.
Conclusion: By understanding the importance of the quality of the environment and the health of society and with the help of jurisprudential teachings, in the framework of the "harmless rule", the sale of building density can be considering due to these facts of this rule which needs to be reviewed by the country's policymakers and housing officials.