Abstract: β-ray induced X-ray spectroscopy (BIXS) is a nondestructive measurement method for tritium in materials. It calculates the content and distribution of tritium in the surface layer (βray range) and bulk by detecting the characteristic Xray and bremsstrahlung Xray spectra induced by tritium in the material and working gas (argon). It is generally believed that the intensity of Ar(Kα) is directly proportional to the tritium content in the surface layer. However, this conclusion is based on the premise that the tritium is uniformly distributed in the surface layer without considering the nonuniform distribution. The influence of the depth profile of tritium on the Ar(Kα) intensity in BIXS spectrum was evaluated in detail. The results show that the contribution of tritium to Ar(Kα) intensity in 1/10 of the maximum range of βrays is about 50% under the condition of uniform distribution. The intensity of Ar(Kα) is several times different from that of uniform distribution under nonuniform distribution. Therefore, in the actual measurement, the results should be modified according to the specific distribution of tritium in the material surface.