An oral nanoparticle (NPs) encapsulated in chitosan/alginate hydrogel (CA-Gel) with dual-sensitive in pH and reactive oxygen species (ROS) was developed to load curcumin (CUR) based on the intracellular-specific characteristics of macrophages. Chondroitin sulfate (CS) wrapped PBAE-SA-PAPE with intracellular pH/ROS dual-sensitive characteristics and CUR via a simple nanoprecipitation method to form NPs (CS-CUR-NPs), and mixed CA-Gel to acquire the final preparation (CS-CUR-NPs-Gel). CS-CUR-NPs displayed an ideal average particle size (179.19 ± 5.61 nm) and high encapsulating efficiency (94.74 ± 1.15%). CS showed a good targeting ability on macrophages and the CA-Gel contribution in protecting NPs from being destroyed in the upper gastrointestinal tract. As expected, CS-CUR-NPs-Gel could significantly alleviate inflammation in DSS-induced UC mice via TLR4-MAPK/NF-κB pathway. This study is the first to attempt to design a novel pH/ROS dual-stimulated release strategy in helping intracellular CUR delivery and anticipated for efficient anti-UC therapy.