Hydrogen in steel trapped by lattice causes hydrogen embrittlement. It is also true in vanadium (V) alloyed high strength steel. These hydrogen trapping behavior, in other words the state of in the profiles obtained by thermal desorption spectrometry (TDS). These TDS profiles effectively analyzed by Gaussian distribution function. profiles of V-alloyed steels are successfully separated into two kinds of traps concerning V alloying, whose peak temperatures are around 140 ℃ and 200 ℃. Owing to the activation energy obtained TDS profiles of different heating rates, they are defined as incoherent and coherent vanadium carbides respectively. Vanadium alloying plays another important role of suppressing the amount of hydrogen trapped along grain boundary. It the improved resistance to hydrogen embrittlement of V alloyed steel. Hydrogen trap along grain boundary is affected by stressing or straining. It to be clarified whether hydrogen trapped along grain boundary causes grain boundary type fracture in hydrogen embrittlement, or it is simply the accompanying phenomenon in hydrogen embrittlement.