Nano-compounding of polyolefins,an economical yet very effective route to high-performance poly-olefin materials,has received considerable attention in recent years. Unlike most of the other polymers,polyolefins are chemically inert,which dictates that nano-compounding of polyolefins has to be con-ducted via in situ polymerization. In this review,a technological progress of the nano-compounding of polyolefins via in situ polymerization technique was summarized thoroughly,with emphasis laid on the current research status of polyolefin/montmorillonite (MMT) nanocomposites. A clear perspective for future researches on this specific family of materials was envisaged. Nano-compounding of polyolefins, an economical yet very effective route to high-performance poly-olefin materials, has received displayed attention in recent years. Unlike most of the other polymers, polyolefins are chemically inert, which dictates that nano-compounding of polyolefins has In this review, a technological progress of the nano-compounding of polyolefins via in in polymerization technique was summarized thoroughly, with emphasis laid on the current research status of polyolefin / montmorillonite (MMT) nanocomposites. A clear perspective for future researches on this specific family of materials was envisaged.