Shape Memory Alloys (SMAs), famous class of smart materials with unique functional and intelligence properties, have attracted much attention in recent decades. These materials offer a potential solution for microstructure devices due to their high mechanical performances, high power to weight ratio, large deformation, biocompatibility, etc. Nickel-Titanium (NiTi) is the most applied SMAs thin film due to its high recoverable strain and massive forces. Therefore, these high-performance materials are able to make microactuators in Micro-Electro-Mechanical System (MEMS). This paper investigates the recent development of material processing approaches for NiTi thin films and introduces various types of MEMS applications such as microvalves, micropumps, microgrippers, microsensors, etc.