Photonic crystal （PC） with a periodic dielectric structure exhibits photonic band gap property. It can produce bright and gorgeous structural colors through physical optics upon interaction with incident light. Over the course of evolution， many organisms， such as peacocks， hummingbirds， and insects， have gradually developed complex photonic crystal structures， progressing from one-dimensional nanostructured photonic gratings or multilayers to three-dimensional colloidal crystals， thereby presenting rich and colorful structural colors. Inspired by nature， researchers have developed a series of innovative visual biosensors by fabricating artificial photonic crystal structures and integrating them into biosensor technology. These biosensors， incorporating photonic crystal structures， can visually respond to various stimuli， such as temperature， stress， environmental pH， and small molecules， by altering lattice parameters， dielectric constants， or Bragg diffraction angles through the combination of photonic crystal chromophoric structures and responsive materials. They show great potential in cell mechanics monitoring， drug transport tracking， bionic skin design， wearable bionic materials， and disease prevention and treatment. This review summarizes the application status of photonic crystals in the field of biosensors， including the basic concept of photonic crystal structure color， the photonic crystal structure phenomena in different dimensions in nature， the temperature， mechanics， environmental pH， and molecular response types of photonic crystal structure color biosensors， and their specific applications. Finally， the development prospects of photonic crystal biosensors in the fields of precision medicine， physiological monitoring， and environmental sensing in the future are prospected， emphasizing the importance of ongoing research and improvement of responsive photonic crystal biosensors， to drive advancements in bionic materials and medical science and technology.