In general, the typical actuation principles of microactuators can be categorized into four folds, electrostatic, piezoelectric, magnetic, and thermal actuations. Among these principles, miniaturization and integration of electrostatic and thermal microactuators with electronic circuits are more feasible. In addition, there are more options of materials for these electrostatic and thermal transducers in microfabrication. In this dissertation, several kinds of novel electro-thermal microactuators are designed, analyzed, fabricated, and characterized.