Liquid heavy metal cooled reactors have the advantage of compact structures, high inherent safety and long service life, which have extensive application prospects on land, sea and deep space. Currently, many powerful countries in nuclear energy R&D have various research priorities and innovations in the development of key technologies for liquid heavy metal cooled reactor projects. This study summarizes the development status and the research progress of liquid heavy metal cooled reactors (mainly concentrated in lead cooled fast reactors) in Russia, United States, China, Europe, Japan and South Korea, and analyzes the performance requirements of liquid heavy metal cooled reactor in various application scenarios. In addition, the core engineering technology of liquid heavy metal reactor is further analytically refined and analyzed. It is suggested that liquid heavy metal cooled reactors technology should prioritize addressing material corrosion and interface compatibility issues, with a focus on optimizing the economic strategies of fuel cycles. Improving cross-scale simulation techniques, strengthening the ability to analyze complex thermal phenomena, validating physical models, accelerating the promotion of full-industry-chain collaboration and multi-functional application expansion are emphasized as the development trend for liquid heavy metal cooled reactors engineering.