Objective Sacral neuromodulation (SNM) has been an effective method to recover and rebuild the bladder function after spinal cord injury (SCI).The mechanism of SNM is still not well understood.It is generally believed that neuromodulation of reflex pathways at the spinal cord level as well as in the supraspinal pathways is involved in this process.At present, it is still a problem how to choose suitable stimulation parameters for effective SNM.We want to improve the effects of SNM by using different stimulation parameters.At present, we are presenting a complete SCI rat model for spastic bladder to study SNM and standardize the surgical procedures and post-operative care.Methods The adult female Sprague-Dawley rats are completely transected in the T9-T10 vertebra after laminectomy in general anesthesia.Some gelfoam is inserted between the cut ends to fill the transection cavity of spinal cord to ensure complete transection.To prevent infection, every rat is introduced penicillin (150 mg/kg) for one week following surgery.Following SCI, the bladder of rats was manually expressed once a day (Credes maneuver).The weight of expressed urine in SCI rats is used to reflect the residual volume and assess the recovery of bladder activity.Results The weight of urine expressed daily increases and reaches at a peak in 1-2 weeks post spinalization.There are all kinds of complications in SCI rats, some leading to death, but the complications can be decreased with proper postoperative care.After several pilot experiments, the surgical procedures and post-operative care are standardized.We consider that the rat model behaves a flaccid bladder in the first 2 weeks after spinalization.After 2 weeks, along the recovery of spinal cord the rat behaves a spastic bladder.The urine retention decreased dramatically, then urges urinary incontinence happens and could be used to study SNM.