Objective The aim of this study was to explore the relationships between the lateral incisions（LI） and cleft extent after palatoplasty with the levator veli palatini retropositioning according to Sommerlad, and acquire optimal indication without lateral releasing incisions in the surgical treatment of cleft palate. Methods A total of 176 patients（81 isolated cleft palate, ICP; 74 unilateral completely cleft palate, UCCP; 21 bilateral completely cleft palate, BCCP） underwent Sommerlad palatoplasty. All dental casts evaluated had been obtained after general anaesthesia. Measuring points on the cast were determined as follows: Cleft palate width（CPW）, interhamular width （IHW）, and cleft palate index（CPI） defined as the ratio of CPW to IHW. The following analysis was carried out: The relationship between CPW and CPI, or between CPW and IHW were determined in both ICP, UCCP and BCCP subjects of both sexes together. Correlation analysis of the cleft palate width（CPW and CPI） and lateral incisions was carried out in ICP, UCCP and BCCP subjects. Results Among 81 patients with ICP, 45 patients（55.6%） had no lateral incisions and bilateral incisions with length ranged from 5 mm to 30 mm（averaged 12.7 mm±10.0 mm） were made in 36 patients（44.4%） after palatoplasty. Among 74 patients with UCCP, no lateral incision was made in 5 patients（6.8%）, unilateral incisions were made in 28 patients（37.8%）, and bilateral incisions were made in 41 patients（55.4%）. Moreover, 21 patients（100%） with BCCP had bilateral incisions after palatoplasty. There was a strong correlation between cleft indexes or cleft palate width and lateral incisions in isolated cleft palate subjects（r= 0.776, P
