Instant analysis of circulating tumor cells (CTCs) heterogeneity has become ahot and difficult topic in current research, and fluorescence enhancement of biomolecules based on localized surface plasmon resonance is method with potential.However, since the measured CTCs signal is highly susceptible to interference from blood background, it is extremely challenging to realize high-sensitivity analysis of CTCs heterogeneity in whole blood. This project is based our previous research on biosensors for real-time monitoring of CTCs and CTCs signal amplification, to construct functional nanoprobebased on localized surface plasmon resonance to differentially enhance the fluorescence signal of heterogeneous CTCs, and then to develop a biosensor system integrating CTCs separation, focusing, signal amplification, measurement and analysis; to solve the problems of background interference, detection signal amplification and specific identification of heterogeneous CTCs, and then to realize instant high-sensitivity analysis of breast cancer CTCs heterogeneity; to study the performance and influencing factors of functional nanoprobe, to explore the laws and influencing factors of the enhancement of CTCs fluorescence signal by functional nanoprobe from the single-cell level, to clarify the action mechanism of the biosensor systemfor instant analysis of breast cancer CTC heterogeneity, and to complete the evaluation and verification via cells and animal models, and then to provide scientific basis and technical support for the development of a real-time and accurate detection system for heterogeneous breast cancer CTCs.