Lactobacillus plantarum 330G4 was encapsulated using natural food-grade materials such as water- and oilphase materials. An ultrasound-assisted double emulsion method was combined with single-factor experiments and response surface methodology to determine the optimal conditions for preparing water-in-oil (W/O) and water-in-oilin-water (W/O/W) encapsulated emulsions. The results revealed that rapeseed oil was an effective oil-phase encapsulating material, whereas pectin and whey protein were water-phase encapsulating materials in the double emulsion method. The volume fraction of the oil phase, mass fraction of the emulsifier, and ultrasound power strongly influenced the encapsulation rate of W/O emulsions. According to response surface optimization, the optimal conditions for W/O emulsion preparation were as follows: whey protein volume fraction of 8%, rapeseed oil volume fraction of 64%, glyceryl ricinoleate mass fraction 3.30%, ultrasound power of 505 W, and reaction time of 30 s. Additionally, the volume fraction of the W/O emulsion, ultrasound power, and reaction time markedly affected the encapsulation rate of W/O/W emulsions. Based on response surface optimization, the optimal conditions for W/O/W emulsion preparation were as follows: pectin mass fraction of 0.25%, W/O emulsion volume fraction of 16.60%, ultrasound power of 75 W, and reaction of time 3 min. The viable count of the encapsulated bacteria was 10.34 lg CFU/mL. The encapsulation rate was 92.82%, stability was 99.06%, and average particle size was 10.53 μm. Compared with the viable count of unencapsulated bacteria after simulated digestion, that of encapsulated bacteria increased by 7.34 lg CFU/mL. Similarly, after heat treatment at 50, 70, and 90 ℃ for 30 min, the numbers of viable encapsulated bacteria were 4.17, 3.20, and 4.58 lg CFU/mL higher than those of their unencapsulated counterparts, respectively. After storage at 25 ℃ for 30 days, the number of viable bacteria increased by 6.05 lg CFU/mL because of encapsulation. Ultrasound-assisted double emulsion to encapsulate L. plantarum improves the activity of probiotics. These findings provide a reference for encapsulation of other probiotics and the enhancement of their activities, while also offering new directions for the development of high-activity probiotic products.