Abstract: Hydrajet fracturing (HJF), which combine jet perforation and hydraulic fracturing, is a relative new stimulation technique in oilfield. The jetting tool using in 101.6 mm casing wells is designed. The treatment tubing are optimized for this well. Though the numerical calculation, the relationship between the jet parameters and displacement is obtained. The proportion of fracturing fluid in oil tubing and test method are given. The HJF technology is made. It was resolved that traditional hydraulic fracture can’t treat effetely in the 4 in well. The above results also showed that this technology can be used in complex condition wells. The paper can provide reference for the further applications of HJF technology.