Objective To investigate the high risk factors, clinical manifestation and therapy strategy of ovarian hyperstimulation syndrome (OHSS) in assisted reproduction techniques (ART). Methods Clinical data of 136 cycles of OHSS patients after in vitro fertilization-embryo transfer (IVF-ET) from 2005 to 2008 were analyzed retrospectively. Results (1) A large number of follicles stimulated, luteal phase supported with hCG and pregnancy were high risk factors to induce OHSS. (2) Most of OHSS occurred on the 3^rd day to 10^th day after administration of medicine to induce ovulation. (3) Longer disease process, more severe symptoms and larger amount albumin used for treatment of OHSS were commonly observed in pregnant patients with OHSS compared with non-pregnant ones. (4) Human serum albumin through intravenous dripping was one of the most successful treatment as plasma expanders through restoration of effective blood volume; paracentesis was necessary for critical OHSS patients with severe ascites and hydrothorax. Conclusions OHSS is a serious complication of controlled ovarian hyperstimulation, which deserves proper prevention and treatment.