At present, the environmental pollution problem caused by the wide application of fiber materials synthesized from petrochemical industry is becoming more and more serious, so it is urgent to develop new green fiber materials. Due to its renewable and degradable properties, fiber plants have attracted much attention in the current environment with an emphasis on green development, especially in the field of reinforced thermoplastic composites. In recent years, the use of fiber plants thermoplastic polymers to obtain composites with excellent properties has gradually developed into a mature technology. In this paper, we summarize the current treatment methods of fiber plants and the latest research results of the application of fiber plants in non-degradable and degradable thermoplastic composites, in order to provide more advanced ideas and methods for the development and utilization of thermoplastic green materials.