Abstract: Objective: To optimize ultrasonic assisted high-pressure water extraction method (UHPE), ultrasonic assisted hot water extraction method (UHWE), and ultrasound assisted enzymatic hydrolysis method (UEH) for polysaccharide extraction from Ganoderma lucidum and examine the bidirectional immunomodulatory activities of polysaccharides extracted using these optimized methods. Methods: Optimization of UHPE, UHWE, and UEH were performed using single factor and response surface experiments, examining the effects of material-liquid ratio, ultrasound time, extraction temperature, extraction time, enzyme concentration, and enzymatic hydrolysis temperature on the polysaccharide yield. UHPE-GLP, UHWE-GLP, and UEH-GLP were prepared separately under the optimal extraction conditions. Based on RAW264.7 macrophages, UHPE-GLP, UHWE-GLP, and UEH-GLP were subjected to investigate the immunomodulatory activities, and their anti-inflammatory activities against lipopolysaccharide (LPS)-induced inflammatory models. Results: The experimental results of process optimization showed that the optimal extraction process of UEH-GLP was as follow: Material-liquid ratio of 1:31 g/mL, ultrasound time of 24 min, enzyme concentration of 5% and enzymatic hydrolysis temperature of 53 ℃. Under these conditions, the GLP yield reached the highest among the three processes, at 10.92%±0.05%. The results of cell experiments showed that, UHPE-GLP, UHWE-GLP, and UEH-GLP could not only enhance immune function of RAW264.7 macrophages by promoting the proliferation, and secretion of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and nitric oxide (NO), but also inhibit immune function by reducing the secretion of TNF-α and NO to suppress the excessive activation of macrophages. These results indicated that UHPE-GLP, UHWE-GLP, and UEH-GLP exhibited excellent bidirectional immunomodulatory activities, among which UEH-GLP showed the most prominent bidirectional immunomodulatory activities. Conclusion: UEH-GLP has significant advantages in yield and bidirectional immunomodulatory activities. This study provides a theoretical basis for the development and utilization of GLP.