We present a category of novel photothermal (PT) microactuators. Each microactuator consists of two PT arms that are jointed at the free end and connected to an anchor at the fixed end. When a laser beam irradiates one of the arms (called hot arm, and the other is cold arm), light energy is absorbed and converted into heat. The asymmetric thermal expansion of the hot and cold arms results in lateral deflection. Based on conduction heat transfer theory and heat dissipation mechanism, we study the PT effects and establish the theoretical model of PT expansion for the microactuators. The temperature distribution and the linear thermal expansion can be numerically calculated. The analytical solution provides an insight into the operation of the actuators and predicts the performance of the actuators with new designs. A symmetry microactuator and a microswitch as the prototypes have been fabricated and tested. The experimental results are in good agreement with the theoretical predictions and prove the feasibility of the novel PT microactuators.