The tolerance of probiotics delivered to the gastrointestinal tract, characterized by high acidity and the abundant presence of digestive enzymes and bile salts, remains unknown. To this end, investigations were conducted involving the compounding of cellulose nanofibril (CN) and sodium alginate (SA), as well utilizing techniques such as Fourier transform infrared spectroscopy differential scanning calorimetry, Luria-Bertani medium liquid culturing, artificial simulated gastrointestinal liquid digestion method, compatibility testing of embedding materials, evaluation of thermal stability after embedding Bacillus coagulum, analysis of pH changes during liquid culture, and assessment of in vitro digestion characteristics (swelling rate, swelling behavior, and pH sensitivity) in artificial simulated gastrointestinal fluids. The results showed that SA had good compatibility with CN, with the addition of nanocellulose effectively enhancing the thermal stability of the SA-CN-BC structure. The pH value of the embedded B. coagulans exhibited minimal fluctuation in the liquid culture, its pivotal contribution to the sustained release. The highest degree of looseness in the gel sphere network and largest swelling rate of 3 243% were observed at a SA:CN ratio of 1:1. The SA-CNBC contracted in the simulated gastric fluid and were expanded in the simulated intestinal fluid, indicating notable pH sensitivity. A pH-sensitive alginate gel-nanocellulose hydrogel sphere was successfully prepared in this study for the delivery of probiotics, demonstrating the potential for hydrogels to serve as biocompatible carriers for drug and nutrient delivery.