At present, refractory anal fistulas, generally known as complex or recurrent complex anal fistulas, are mostly high complexity fistulas. In addition to the complex shape of the fistula, the differences in the organization of the fistula are also an important issue in the difficulty of recovery from treatment. With the development of high-tech medical imaging technology, the anatomy of complex anal fistula is becoming clearer and clearer in imaging diagnosis. 3D ultrasound and 3D magnetic resonance film imaging can clearly show the internal opening of the fistula, the shape of the fistula, whether there is a cystic cavity and the adjacent relationship with the sacro-coccyx and rectum before surgery, laying the foundation for one-time surgery to eradicate the fistula. Especially for cystogenic fistulas, the size and number of cystic cavities determine the surgical route and plan.