Halal food is food whose halal status is regulated by sharia institutions such as LPPOM MUI which is set by the government. The halal status of food must be traced from the process of raw materials, processing, packaging, transportation, and distribution to the final consumer. It is difficult to trace the certainty of halal food, especially beef in Medan City because the supply chain information from upstream to downstream is not transparent. To increase the transparency of beef status and increase consumer confidence, especially Muslim consumers, a distributed and transparent system is needed, where many parties can access the status of food at any time. So Blockchain technology is used to help track the halal status of beef along the supply chain. The purpose of this study is to design a system to obtain information certainty that beef distributed along the supply chain is halal and safe for consumption by utilizing Blockchain technology and to increase public safety and trust in the LPPOM MUI halal certification system. Based on the discussion and research analysis, it is known that the information in the halal beef supply chain in Medan City uses blockchain technology designed with a data security system using smart contracts, where information that has been stored cannot be changed by any party. so that there is a guarantee of information security in the beef supply chain in the city of Medan. This research is expected to support transparency, security, and certainty of information about halal beef in Medan City.