As abrasive water jet (AWJ) started to be used in industry, especially in aerospace and automotive industries extensively, cutting precision and accuracy has become a major requirement for further application. Unlike a knife which retains a fixed shape as it cuts through material, an AWJ stream is constantly changing. It bounces back-and-forth during cutting process. As a result, a typical surface cut by AWJ displays striation marks on the cutting surface. AWJ’s cutting front can be distinguished as a smooth upper zone and a rough lower zone. As being an energy dissipation beam cutting process, the striation marks couldn’t be eliminated completely on the cutting surface. But, by selecting proper parameters, smoother surface can be generated. However, high quality also means high cost. In manufacturing process, it is desirable to produce qualified parts with the lowest cost. This paper explored all parameters which might affect surface roughness. Based on the experimental results, an empirical model has been built and tested. With this model, predicting surface roughness becomes possible before actual cutting.