Objective To study the incidence and cause of ultrafiltration failure(UF) in peritoneal dialysis patients. Methods Respective analysis method was applied to investigate the relationship of the duration of peritoneal dialysis, peritonitis, serum albumin, high glucose accumulation(GA), peritoneal small molecular weight solute transport rate(PET),and peritoneal neoangiogenesis evaluated by detecting of the expression facter VIII by immunohistochemistry. Result The longer dialysis lasted,the higher rate of UF occured. GA and PET was higher, the increased expression of peritoneal neoangiogensis and serum albumin was lower in UF group compared with normal group. Peritonitis had no difference in two groups. Conclusion UF is mainly related with the duration of peritoneal dialysis and peritoneal neoangiogenesis.