The invention discloses a sensor with a gold nanoparticle and quantum dot composite structure, a system and a method. Based on the local surface plasma resonance characteristics of the gold nanoparticles under total internal reflection, the microfluid technology is combined, the gold nanoparticles are directly combined with the transparent substrate, the binding force is strong, the thickness is accurate and controllable, the continuity is good, no pollution is caused, in addition, the optical property of the gold film is excellent, and the sensitivity and the accuracy are very good. Quantum dots are inserted into gaps among gold nanoparticles to obtain a gold nanoparticle quantum dot composite structure, the surface plasma resonance effect of the gold nanoparticles is enhanced, the sensoris more sensitive to changes of parameters such as the refractive index and the thickness of the composite structure and media nearby the composite structure, and research substances attached to thesurface of the structure can be detected more easily. The sensor has the advantages of high sensitivity, high stability, no marking, no damage, high accuracy, real-time rapid detection, wide application range and the like; the sensor has a great development prospect and a wide potential application value.