Objective:To investigate clinical features and imageology of renal cysts of high density, containing proteinaceous fluid and increase the diagnosis and treatment level of this special type renal cyst. Methods:Six cases were proven to be renal cysts of high density(pathologically) from 2002 to 2007 were reviewed. Among 6 cases, 1 was in the upper pole of kidney, 4 were medial and 1 was located in the anus perineum . All were 2-5 cm in size. Ultrasonography(US) excretory unognaphy, multiphase CT and renal angiography DSA imaging was performed for preoperative diagnosis. The preoperative diagnosis found renal neoplasms in 4 and renal cysts in 2. All of them were operated by partial nephrectomy. Results:All of the 6 renal high density renal masses were resected surgically, which were proved pathologically to be renal cysts; high density present. All of them contained proteinaceous fluid with benign cyst walls on histologic examination. No recurrence was seen in any of these cases during a long follow-up. Conclusion:CT and B-US have a higher diagnostic value, which can show the internal shape and character better. B-US or CT guided puncturing biopsy can be better applied to atypical renal cysts. Once the correct diagnosis is acquired, laparoscopic surgical treatment should be carried out.