The invention relates to the technical field of functional nanomaterials, and in particular to a multifunctional mesoporous carbon microsphere integrated with T1-T2 dual mode nuclear magnetic imaging and drug-loading property and a preparation method thereof. The multifunctional mesoporous carbon microsphere disclosed by the invention contains paramagnetic gadolinium phosphate as a T1 contrast agent and superparamagnetic iron oxide as a T2 contrast agent, the particles of the contrast agents are highly uniformly dispersed in the carbon skeleton of the mesoporous carbon microsphere, the mass content of gadolinium phosphate and iron oxide is 0.5 to 25 percent, and the particle size of gadolinium phosphate and iron oxide is 1nm to 10nm. In the process of preparing the multifunctional mesoporous carbon microsphere, an iron-gadolinium metal cluster is introduced into a precursor of the mesoporous carbon microsphere in one step, and the multifunctional mesoporous carbon microsphere is then prepared by one-step in-situ carbonization. The multifunctional mesoporous carbon microsphere realizes the integration of a T1-T2 dual mode contrast function and a drug-loading function, also has the characteristic of low cytotoxicity, realizes a diagnosis- and treatment-integrated function, and has a broad application prospect in clinical and basic medicine researches.