Abstract: Thermoplastics reinforced by fibrils of thermotropic liquid crystalline polymers,so-called in-situ composites,have shown a new approach to reinforcing thermoplastics.Recent research works on in-situ composites are reviewed on the.a.spects of material ingredients,microstrucfiure and morphology,performances,processing and cost.A comparison of in-situ composites with fiber-reinforced thermoplastics has been conducted,which indicates the advantage,potential and prosperous future of this new approach.