Abstract: Objective　To investigate clinical features and cyclin-dependent kinase-like 5 (CDKL5) mutations in 3 cases with early epileptic encephalopathies（EEEs ） Methods　Clinical data of 3 cases with EEEs were retrospectively analyzed. Next generation sequencing (NGS) was used to detect CDKL5 genes mutations, and Sanger sequencing was performed to confirm the mutations identified by NGS. Results　The three patients are one male and two females, aged 3 years old, 8 years old and 3 months old, respectively. Case one was found to have a hemizygous mutation c. 2854 C＞T in CDKL5 which was inherited from his mother, case two was found to have a de novo nonsense mutation c.858 C＞A，and case 3 was found to have a de novo frame shift mutation c. 1363delG. Conclusions　The mutation in CDKL5 lead to EEEs, and the newly found c. 1363delG expands the mutation spectrum of the CDKL5 gene．