<p>The development of intelligent sensors with enhanced stability and sensitivity is imperative for the expeditious, precise and on-site monitoring of food and health. Because of the widespread popularity, portability and powerful imaging capability of smartphones, smartphone-integrated intelligent sensors have gradually become ideal devices for portable sensing. These sensors rely on diverse sensing materials, including carbon-based nanomaterials, metal/metal oxide nanoparticles, metal-organic frameworks (MOFs), covalent organic frameworks (COFs), MXenes, and single-atom materials (SAMs), offering unique physicochemical properties for target recognition and signal amplification. The sensing performance is predominantly governed by the active sites. However, a systematic review on the optimization strategies of sensing materials is still lacking. Here, we systematically discuss the optimization strategies of the sensing materials, including regulations of nonmetal active sites, metal active sites, metal coordination environment, and defect sites. Then, some emerging sensing materials, MOFs, COFs, MXenes and SAMs are briefly introduced. Subsequently, the applications of intelligent electrochemical sensors in food safety monitoring and health monitoring are summarized. Finally, the development prospects of smartphone-integrated electrochemical sensors are put forward. This review is helpful to the design of sensitive and reliable detection methods based on smartphones.</p>