Objective By constructing the clinical symptom evaluation system of patients with Cavum Septum Pellucidum（ CSP） combined with Cavum Vergae（ CV）， and the changes of cysts volume before and after operation， we want to find out the evaluation indicators that can quantitatively predict the prognosis of patients with CSP combined with CV. Methods Nine patients with CSP combined with CV diagnosed by MRI were recruited. Firstly， the reduction rate of cyst was calculated by preoperative and postoperative MRI data. Secondly， according to the characteristics of clinical symptoms， the clinical symptoms were scored， and the clinical symptom scoring system was established. Finally， the correlation between clinical symptoms and objective imaging quantitative data of cyst shall be find out. Results The clinical symptom scores and cyst volume after operation were significantly lower than those before operation， and the differences were statistically significant（ t' values are 6.36 and 5.06， respectively，P＜ 0.01）. There was no significant correlation between preoperative cyst volume and preoperative clinical symptom scores of children（ r=0.018， P＞0.05）. There was no significant correlation between clinical symptom score and cyst volume（ r=0.520， P＞0.05）. There was a positive correlation between the improvement of clinical symptom score and the reduction rate of cyst volume （r=0.843，P=0.009）. There was a negative correlation between the improvement of clinical symptom score and the volume of cyst（ r=-0.738， P=0.037）. Conclusions As one of the surgical methods of CSP combined with CV， neuroendoscopic surgery can significantly improve the postoperative symptoms. Postoperative cyst reduction rate and postoperative cyst volume can be used as independent quantitative predictors of the postoperative prognosis of patients with symptomatic CSP with CV.