It is very important to investigate a shock wave / turbulent-boundary-layer interaction for the prediction of compressible flows. For this problem numerical procedures have been making rapid progress, for example TVD scheme, but turbulence models have not. This is partly because there is scarecely available data of compressible flows with a shock wave. However, recently a direct numerical simulation can be done and the results will be used to modify compressible turbulence models. I studied a compressible k-ε model. The propriety of k equation was investigated for the 1-dimensional turbulent flow passing through a normal shock wave. I found that the mean pressure gradient / velocity fluctuation correlation term in k equation plays the most important role in the behaviour of turbulence.