Abrasive waterjet (AWJ) is a promising method owing to the advantages of non-thermal effect and high removal rate. However, the high consumption of garnet abrasive has limited the development of AWJ technology. In this study, steel slag, which is a typical solid waste, was used as abrasive particles instead of garnet for abrasive waterjet (GAWJ) cutting for the first time. Stainless steel was used as specimen in the experiments to estimate the machining performance of steel slag abrasive waterjet (SAWJ). The results showed that SAWJ produced a cutting wear zone (CWZ) and a striation zone (SZ) on the cross-section surface compared to GAWJ. It produces longer SZ with dense and shallow striations on the surface compared to GAWJ. The influence of process parameters on the kerf produced by GAWJ and SAWJ is almost the same. SAWJ creates a finer kerf, contributing to higher cutting accuracy and less waste of substrate material. For material removal rate and roughness, performance similar to GAWJ can also be achieved. The SEM image reveals that micro cutting and plowing are the main material removal mechanisms for SAWJ cutting stainless steel. The cutting efficiency of SAWJ is about 90 % that of GAWJ, but the cutting efficiency per unit price can reach more than 260 %. The substitution of abrasives using steel slag is expected to bring about a 45 % reduction in operating expenses for the AWJ factories, potentially generating $8.34 million in annual savings for the Chinese AWJ industry.