A new, slack, and uniformly porous TiO2 material is synthesized by a simple, carbon nanotube (CNT) template-assisted I hydrothermal method and is further explored for protein immobilization and biosensing. Results demonstrate that the material I has a large specific surface area and a unique nanostructure with a uniform pore-size distribution. Glucose oxidase (GOD) immobilized on the material exhibits facile, direct electrochemistry and good electrocatalytic performance without any electron mediator. The fabricated glucose oxidase sensor shows good stability and high sensitivity, which indicates that the slack porous TiO2 is an attractive material for use in the fabrication of biosensors, particularly enzymatic sensors, because of its direct electrochemistry, high specific surface area, and unique nanostructure for efficient immobilization of biomolecules.