[Abstract] Objective: To discuss the characteristics of trichilemmal cyst and epidermoid cyst on clinic and two-dimensional ultrasonography. Methods: Collect 44 cases of trichilemmal cyst and 276 cases of epidermoid cyst confirmed by pathology after surgery, compare the differences of sex, age, distribution, location, size, boundary, morphology, internal echo, posterior echo and blood flow situation between these two groups. Results: Differences between the two groups which were statistically significant (P<0.05) include: (1)Age：the mean age of trichilemmal cyst group was（47.56±13.88y）and the mean age of epidermoid?cyst group was（37.30±19.29y）.(2)Distribution: 31（70.45%）and 7（2.54%）masses of trichilemmal cyst and epidermoid cyst located on scalp respectively.(3)Calcification in the masses: 38（86.36%）masses of trichilemmal cyst and 29（10.51%）masses of epidermoid cyst.(4)Liquify area in the masses: 40（90.91%）masses of trichilemmal cyst and 20（7.25%）masses of epidermoid cyst. However on sex, location, size, boundary, morphology, posterior echo and blood flow situation, difference between the two groups was not statistically significant (P>0.05). Conclusion: trichilemmal cyst and epidermoid cyst were usually weak echo masses on skin and subcutaneous?layer with clear boundary and regular morphology.The posterior echo of these two kinds of masses often enhanced and no blood flow inside or around the masses. But the age of trichilemmal cyst was a little bit older than epidermoid cyst, and most of the masses located on scalp with calcification and liquify area inside. These features were useful for differential diagnosis.