Pseudomonas aeruginosa (PA) is a major cause of hospital-acquired infections. It can survive in a variety of extreme environments, and is highly resistant to antibiotics. PA can attack immunocompromised populations to cause severe infections, being a major cause of mortality in clinical practice. Therefore, rapid diagnosis of PA is critical for infection control. Conventional detection techniques such as plate assays, immunoassays, and nucleic acid assays have excellent accuracy and sensitivity, while they are costly and time-consuming. In recent years, novel biosensing technologies have achieved ultrasensitive and precise detection of PA by integrating various biorecognition elements and signal enhancement strategies, providing an efficient, convenient, and cost-effective solution for the rapid identification, treatment, and control of PA. In this paper, we systematically review the principles, application progress, and challenges of magnetic separation biosensing technologies based on electrochemical, optical, CRISPR/Cas12a system, and magnetic nanoparticles, and provide future research directions, aiming to promote the innovation and clinical application of the technologies for rapid detection of PA.