Abstract: The structure,morphology and sensing mechanism of TiO₂:Nb₂O₅ composite crystalloid were analyzed by using X-ray diffraction（XRD） and scanning electron microscopy（SEM）.The results show that the titanium rich sample with 10% niobium has large amount of oxide vacancy and intergrain porosity augment,that enhances electrical conductivity and gas sensitivity of the material.Resistance R_a and sensitivity K of the sample are improved simultaneously.It may serve as a new way for measuring the freshness of meat and fish.