If the right testicle is swollen and painful, two diseases should be noted: acute testicular torsion and acute testicular epididymitis, which can be confirmed by scrotal ultrasound examination. The imaging manifestation of testicular torsion ultrasound is that the arterial blood supply to the testicle is reduced, the blood flow becomes slower, the testicle is enlarged, and the spermatic cord is twisted; the manifestation of acute testicular epididymitis ultrasound is that the arterial blood supply to the testicle is abundant, which is the typical difference between the two. Acute testicular torsion requires emergency surgery; while acute testicular epididymitis requires bed rest and anti-inflammatory treatment with broad-spectrum antibacterial agents, which takes 5-7 days.