Crohn's disease (CD) is a chronic nonspecific intestinal inflammatory disease with unclear etiology and pathogenesis, it may occur different types of perianal lesions. Clinical evaluation modalities for perianal CD (PCD) are including Perianal Disease Activity Index (PDAI), computed tomography (CT), fistula angiography, Magnetic Resonance Imaging (MRI), examination under anesthesia(EUA), endoscopy (Endoscope) and ultrasound (ultrasonography, US). Each has its advantages and convenient for the diagnosis and identification of PCD. Moreover, the application of US in the assessment of fistula activity and follow up of PCD after treatment also provides valuable help for the clinic. Timely diagnosis of PCD helps in early diagnosis of CD and is of great significance for clinicians to make a more effective treatment, which can improve the quality of the patients’ life. This paper reviews the progress of US in the diagnosis and treatment of PCD.