Objectives: In this study, we aimed to establish an efficient method for the extraction of radix Morindae officinalispolysaccharide (MOP) by applying ultrasonic technology and by optimizing the parameters through response surface methodology (RSM) based on the central composite design. Materials and Methods: Ultrasound-assisted enzymatic extraction (UAEE) was performed to extract the MOP. We applied an orthogonal array design to optimize the concentration of enzymes (cellulose, pectinase, and papain). The extraction parameters were optimized based on the RSM technique. Furthermore, the effects of ultrasound-assisted enzymatic treatment on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity by the MOP was optimized using the RSM technique. Results: According to our results, 1.0% cellulase, 1.5% pectinase, and 1.0% papain were the optimum concentrations of the enzyme (calculated based on the percentage dry weight of radix Morindae officinalis powder). The optimum conditions of extraction were as follows: 21 mL/g solvent–solid ratio, 280 W, pH of 5.3, and temperature of 50°C. Under these conditions, the yield of MOPs and DPPH-scavenging activity of MOP were 23.68% ± 0.52% (n = 3) and 117.26 ± 2.73 mg Vitamin C/100 g dry weight (n = 3), respectively. The overall desirability was 1.03 ± 0.01 (n = 3). Conclusion: UAEE was effective in the extraction of MOP, and RSM technique was adequate to design and optimize the extraction parameters.