The invention provides an amorphous calcium carbonate nanosheet material and a preparation method thereof. Tellurium nanowires are washed, and washed tellurium nanowires are obtained; then a tellurium nanowire solution is prepared from the washed tellurium nanowires, the tellurium nanowire solution, a carbon source and a calcium source have a reaction, and the amorphous calcium carbonate nanosheet material is obtained; the zeta potential of the washed tellurium nanowires is controlled to be smaller than or equal to minus 14 mV, the volume ratio of the tellurium nanowires to a first solvent is controlled to be (0.2-10):1, so that one-dimensional tellurium nanowire materials used as formworks can induce the calcium source to react with the carbon source, amorphous calcium carbonate is obtained, and the nanosheet material can be further assembled. Meanwhile, according to the preparation method, materials of the formworks are simple and easy to obtain, the preparation method is simple and controllable, and batch production is facilitated.