The article reviews the latest advancements in nanogel-based chemotherapy drug delivery systems, focusing on the role of functional groups in drug loading and the design of smart hydrogels with controlled release mechanisms. Nanogels, composed of natural and synthetic polymers such as chitosan, alginate, and polyacrylic acid, have been developed for chemotherapy drug delivery. Functional groups like carboxyl, disulfide, and hydroxyl play crucial roles in drug encapsulation and release. Smart hydrogels have been engineered to respond to tumor microenvironmental cues such as pH, redox potential, temperature, and external stimuli like light and ultrasound, enabling targeted drug release. The use of functional groups in nanogel preparation allows for the creation of multifunctional nanogels with high drug loading capacity, controllable release, and good targeting. These nanogels have shown promising results in preclinical studies, with enhanced antitumor effects and reduced systemic toxicity compared to traditional chemotherapy. The development of smart nanogels with functional group-mediated drug delivery and controlled release strategies represents a promising direction in cancer therapy, offering improved patient outcomes by enhancing drug targeting and minimizing adverse effects.The article reviews the latest advancements in nanogel-based chemotherapy drug delivery systems, focusing on the role of functional groups in drug loading and the design of smart hydrogels with controlled release mechanisms. Nanogels, composed of natural and synthetic polymers such as chitosan, alginate, and polyacrylic acid, have been developed for chemotherapy drug delivery. Functional groups like carboxyl, disulfide, and hydroxyl play crucial roles in drug encapsulation and release. Smart hydrogels have been engineered to respond to tumor microenvironmental cues such as pH, redox potential, temperature, and external stimuli like light and ultrasound, enabling targeted drug release. The use of functional groups in nanogel preparation allows for the creation of multifunctional nanogels with high drug loading capacity, controllable release, and good targeting. These nanogels have shown promising results in preclinical studies, with enhanced antitumor effects and reduced systemic toxicity compared to traditional chemotherapy. The development of smart nanogels with functional group-mediated drug delivery and controlled release strategies represents a promising direction in cancer therapy, offering improved patient outcomes by enhancing drug targeting and minimizing adverse effects.