Bioactivity and stress shielding are the most important problems of medical implanted porous titanium. In this study, porous titanium with 40% porosity was prepared by one-step spark plasma sintered (SPS) technology, and the surface of porous titanium was modified by a simplified alkali treatment method. The effects of a high concentration on pore properties, mechanical properties, and biological activities of porous titanium were investigated. The results show that the surface of porous titanium treated with a high concentration of alkali forms an interconnected network layer, which provides nucleation points for the formation of apatite. Porous titanium can still meet the requirements of hard tissue replacement after treatment with high-concentration alkali solution (yield strength (130 MPa) and elastic modulus (6.0 GPa)). A layer of apatite is formed on the surface of porous titanium after alkali treatment. The ability of inducing apatite formation increases with the increase of lye concentration. In addition, the results of proliferation and live dead cell staining of bone mesenchymal stem cells (BMSC) showed that alkali treatment had no toxic effect on the cells. With the increase of concentration, the cell activity was significantly enhanced. Therefore, the bioactive porous titanium modified with simplified alkali has a good medical prospect as artificial bone material.