Objective　To choose the optimal surgical plane through preoperative anatomical observation and recognition of Toldt's gap in CT images, so that perspective customized surgical approach can be made. Methods　246 patients underwent laparoscopic surgery for colorectal cancer in Shunde First People's Hospital affiliated to Southern Medical University from January 2010 to June 2012 were chosen, location, communication and adjacent structures of Toldt's gap in preoperative CT images and direct intraoperative laparoscopy images was observed and compared.　Results　The fusion of the posterior wall of the ascending and descending mesocolon to the anterior renal fascia was identified in the CT images as the Toldt 's line. Good consistency of Toldt's fascial spacein preoperative CT images and intraoperative view was obtained (Kappa = 0.718). By incising along this line while referencing to the retromesenteric plane during the laparoscopic surgery for colorectal cancer, correct surgical plane can be established.　Conclusion　①Preoperative CT scan can be adopted to identify the correct Toldt's space as the surgical plane and preserve the integrity of the prerenal fascia. ② CT scan can indicate whether there is any tumor invasion to Toldt 's space, which is of great perspective significance in formulating customized surgical plan and assessing the prognosis.