Single-molecular magnets (SMMs) that display magnetic bistability and slow relaxation process have unique potential in ultrahigh-density memory components and spintronic devices. Lanthanide-based SMIVIs (Ln-SMMs) have sparked increasing interest recently due to the large magnetic moments and large magnetic anisotropy. A few reviews about lanthanide-based SMMs have been reported, which mainly focused on their syntheses, structures and magnetic properties. The present review concentrates on following aspects: (1) strategies of constructing Ln-SMMs showing high anisotropy energy barriers, (2) understanding the complex relaxation mechanisms, and (3) tunable magnetic dynamics and multifunctional properties of the lanthanide-based SMIVIs. The work will help us better understand the chemical and physical natures of the Ln-SMMs, and provides new routes in designing new lanthanide-based SMMs with interesting magnetic and multifunctional properties.