The work aims to polishing the inner surface of tubule or microholes which is hard to do by traditional polishing method. A novel abrasive flow polishing method (SOAFP) based on self-oscillation pulse characteristics was proposed. Self-excited oscillation cavity was used to produce the pulsation of abrasive flow, which can efficiently polish the inner surface of the tubule or microhole. The mathematical model was established and the numerical simulation was carried out, the structural parameters d2/d1, L/D and transition angle β were obtained. The experimental platform was built and the effectiveness of SOAFP was verified by experiments. The result shows that the roughness of the inner surface of stainless steel tubule Ra was reduced from 480 nm to 50 nm after 12 hours of processing of SOAFP, with no obvious directional texture, and 14 hours later, the inner surface of stainless steel tubule had obvious mirror effect. In the case of non-oscillation cavity, the surface roughness of the inner wall of the tubule was 55 nm after 14 hours of polishing, and there was obvious directional texture on the inner surface. The simulation and experiments show the effectiveness of self-excited oscillation pulse effect polishing method (SOAFP), and the improvement of polishing effect and quality by the structure parameters of the structural parameters d2/d1, L/D and transition angle β.