In order to ensure the security and stability of communication and the integrity of data transmission, an intelligent detection of link defects in multi-core optical fiber network based on incoherent optical frequency domain re- flection is proposed. Firstly, the mathematical model of multi-core optical fiber network is constructed, and the optical fiber node mapping and spectrum allocation are constrained, so that the minimum frequency spectrum occupies the maximum number of frequency gaps. Then the data transmission link model is established by cluster detection, and the communication transmission function is obtained. The link is adjusted according to the correlation matching filter, and the link data is collected by baud interval balancing. Finally, Rayleigh scattered light waves generated by incoherent optical frequency domain reflection step frequency modulation are used to obtain the spatial distribution position of net- work health by combining with inverse Fourier transform to realize intelligent detection of multi-core optical fiber net- work link defects. The experimental results show that the proposed method can accurately detect link defects, with de- tection errors of less than 0. 4%, 0. 2%, and 0. 5 for link blocking defect detection, link average fault risk detection rate, and link spectrum utilization defect detection, respectively. The detection time is controlled within 1. 5 seconds, which can help the network recover operation in a timely manner.