Abstract: 【Objective】 The study was conducted to prepare T1 contrast agents with low toxicity and good relaxation performance.【Method】 Attapulgite-polyacrylic acid-gadolinium carbonate ternary composites were prepared with attapulgite as substrate by the method of simulating biological mineralization. The structure of the composite was characterized by using Fourier transform infrared spectroscopy（FTIR）,thermogravimetric（TG）,X-ray diffraction（XRD） and transmission electron microscopy（TEM）.【Result】 The three components in the composite were evenly distributed and closely combined,and the rod-like crystal structure of attapulgite was intact. In vitro toxicity test showed that the prepared compounds had negligible toxicity to normal human cells. The rates of longitudinal and transverse relaxation of the complex were 5. 47 and 20. 19 mmol/（L·s）,respectively.【Conclusion】 The n-ATP-PAA-Gd composite prepared in this study had good relaxation performance and might achieve good contrast effect,which hence could be expected to be a new T1 contrast agent.