Objective: This study focuses on improving the stability and water solubility of astaxanthin. Methods: Phytosterol α-linolenic acid ester was synthesized by chemical method with phytosterol andα-linolenic acid as raw materials. Liposomes co-encapsulating astaxanthin and phytosterol α-linolenic acid ester were prepared by employing a thin-film ultrasound technique with the utilization of soybean phospholipid. Results: Based on the structure analysis by infrared spectroscopy and nuclear magnetic resonance, it has been demonstrated that the product was phytosterolα-linolenic acid ester. The purity of phytosterolα-linolenic acid ester was (90.72±2.09)% by gas chromatography. The encapsulation efficiency of liposomes co-encapsulating astaxanthin and phytosterolα-linolenic acid ester were (95.00±0.66)%,the average particle size was (158.70±9.70)nm, the polydispersity index (PDI) was 0.35±0.02, and the average zeta potential was (-33.87±2.48) mV. Transmission electron microscopy revealed that the complex liposomes were spherical with regular shape and uniform particle size distribution. Conclusion: Phytosterol α-linolenic acid ester could be applied in the preparation of astaxanthin-loaded liposomes.