Abstract: Monodisperse silica spheres with a diameter of 640 nm were used as template, carbon nitride precursor was made by refluxing and stirring ethylendiamine (CH₂NH₂)₂ and carbon tetrachloride (CCl₄). The precursor was infiltrated into the interstitial regions of the silica template and heat-treated in nitrogen atmosphere to form a carbon nitride/silica composite, then macroporous carbon nitride was gained by removing the silica template with HF solution treatment. The composition and structure of a macroporous carbon nitride sample was detected by X-ray powder diffraction (XRD), elemental analysis, selected area electron diffraction (SAED), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectra (XPS). The in vitro anticoagulation activity of the sample was evaluated by activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT). It is found that the macroporous carbon nitride has no influence on the anticoagulation activity of plasma. It indicates that the potential application of the 3D macroporous carbon nitride as blood compatibility materials in the biomedical area will be realized in the future.