Liquid crystal elastomer soft actuators, with their unique liquid crystal anisotropy and rubber soft elastic properties, have shown sensitive response to multiple stimuli and the ability to perform complex large deformation, which has become a research hotspot in the field of scientific research. Among them, liquid crystal elastomer soft pneumatic actuators have attracted much attention due to their simple actuation mode and mild actuation-conditions. Recently, researchers have studied the actuation mode, response speed, and recovery speed of liquid crystal elastomer soft pneumatic actuators, and broadened their mechanical and optical applications. In this review, the latest research trends of liquid crystal elastomer soft pneumatic actuators are reviewed, their abnormal mechanical behavior is introduced, and the potential application prospects of this technology in the fields of mechanics and optics are discussed prospectively, which provides a new perspective and enlightenment for the research and development of related fields.