Indonesia has been regulated housing development in Law Number 1 of 2011, in practice many developers carry out housing development business using land owned by other parties with a cooperation system for building. When the housing developers make an agreement to use land belonging to someone else, in its implementation it is often ended up being a legal case. This study aims to analyze and find solutions to legal problems related to the legal force of the cooperation build and sharing agreement in terms of Law Number 1 of 2011 and Law Number 2 of 2014, as well as analyzing legal protection for land owners as result of tort committed by developers of the build and sharing agreement in case Number 177/Pdt.G/2020/PN Ptk in terms of the Civil Code and Government Regulation Number 24 of 1997. This research is a juridical-normative research with data collection method in the form of literature study based on secondary data. The type of approach used is a case approach, a statutory approach and a conceptual approach with qualitative data analysis techniques. The result of this research is that the legal force of the cooperation agreement deed has perfect legal force and is binding on the parties because it has been made in accordance with Law Number 1 of 2011 and Law Number 2 of 2014. From here the legal protection obtained by the land owner through Decision Number 177/Pdt.G/2020/PN Ptk with the cancellation of the deed of build and sharing agreement, for the benefit of Mrs. Asnah et al as the Plaintiffs, were ordered to be returned to their original state by clearing the land by the Defendants who occupied the land belonging to the Plaintiffs.