Magnetic resonance imaging (MRI) plays an important role in precision medicine that is hampered by the lack of contrast agents with high efficiency and the ability to translate diagnostic accuracy into therapeutic intervention. Herein, we demonstrate a DNA-based MRI probe that overcomes previous single-mode enhancement and provides a mechanism of action for aggregation-induced dual-mode MRI signal enhancement. A facile method is developed to produce aggregated T1/T2 dual-mode NaGdF4:Dy@PDA-DNA MRI probes. When aggregated, this probe can further amplify MRI signal intensity and exhibits improved geometrical and positional stability in vivo. The performance of the NaGdF4:Dy@PDA-DNA MRI probe toward MRI-guided preoperative planning and visualization-guided surgery is verified using an orthotopic tumor-bearing mouse model. The result shows that the rapid metabolism of the degraded probe leads to the mitigation of long-term toxic effects. Therefore, the developed high-performance MRI probe is of great significance for enhancing MRI diagnostic accuracy into precision medical therapeutic interventions.