Two-dimensional (2D) nanomaterials have been widely used in biomedical applications because of their biocompatibility. Considering the high risk of exposure of the circulatory system to TiCT, we studied the cytocompatibility of TiCT MXene with red blood cells (RBCs) and human umbilical vein endothelial cells (HUVECs) and showed that TiCT had excellent compatibility with the two cell lines. TiCT at a concentration as high as 200 μg/mL caused a negligible percent hemolysis of 0.8%. By contrast, at the same treatment concentration, graphene oxide (GO) caused a high percent hemolysis of 50.8%. Scanning electron microscopy revealed that RBC structures remained intact in the TiCT treatment group, whereas those in the GO group completely deformed, sunk, and shrunk, which resulted in the release of cell contents. This difference can be largely ascribed to the distinct surficial properties of the two nanosheets. In specific, the fully covered surface-terminating -O and -OH groups leading to TiCT had a very hydrophilic surface, thereby hindering its penetration into the highly hydrophobic interior of the cell membrane. However, the strong direct van der Waals attractions coordinated with hydrophobic interactions between the unoxidized regions of GO and the lipid hydrophobic tails can still damage the integrity of the cell membranes. In addition, the sharp and keen-edged corners of GO may also facilitate its relatively strong cell membrane damage effects than TiCT. Thus, the excellent cell membrane compatibility of TiCT nanosheets and their ultraweak capacity to provoke excessive ROS generation endowed them with much better compatibility with HUVECs than GO nanosheets. These results indicate that TiCT has much better cytocompatibility than GO and provide a valuable reference for the future biomedical applications of TiCT.