Experimental research on magnetic abrasive finishing for GH4169 alloy fuel injector of nickel based alloy was carried out and analyze the deburring effect of the built-in auxiliary pole magnetic abrasive finishing on the inner surface of the workpiece and the cross hole line. The Aurora built-in auxiliary magnetic abrasive machining was used to grind and process the inner surface of workpiece and internal cross hole line. The movements like scratch, grinding, etc. between the abrasive particles and the workpiece were adopted to improve the quality of the workpiece surface and remove the cross hole line burr. The magnetic abrasive with yoke speed of 1000 r/min, cylindrical auxiliary pole, machining gap of 6 mm and average grain size of 250 μm could provide better machining effects and higher efficiency than the traditional processing. The surface roughness of the detected workpiece could drop to 0.47 μm from the original 5.8 μm (Ra<0.5 ?m). The burr at the internal cross hole line was obviously removed and the second finishing process could be conducted due to the abrasive action of magnetic particles. The built-in auxiliary pole magnetic abrasive finishing method can be adopted to improve the folds and minor cracks on the surface of the original workpiece and remove the burr at the cross hole line. When the particle size of the magnetic abrasive particle is 250 ?m, the grinding effect is the best. After finishing by magnetic abrasive finishing, the pipe can get good surface effect and improve the comprehensive performance of the pipe.