Abstract <p>Sweat contains various substances that can indicate physiological parameters of the human body, indirectly reflecting the body’s fluid balance and overall health status. The pH value is an important indicator that can reflect skin health. Accurate detection of pH in sweat can provide insights into an individual’s health condition, making it highly significant in health management and disease prevention. In this study, a wireless, wearable sweat detection system based on a smartphone was designed. Gold nanoparticles and polyaniline were used to modify flexible screen-printed electrodes, and the open-circuit potential-time curve was employed to characterize the performance of the pH sensor. Experimental results show that the fabricated pH sensor exhibits a good linear response, stability, and repeatability, with a sensitivity of 63.04 mV/pH. The test results of the developed sweat detection system demonstrate its ability to accurately measure the pH value in sweat, indicating broad application prospects in the field of wearable sweat sensors and systems.</p>