Abstract: Objective　Related factors of pediatric obstructive sleep apnea hypopnea syndrome (OSAHS) combined with attention deficit hyperactivity disorder (ADHD) were retrospectively analyzed in OSAHS children. Methods　The research included 437 cases of children hospitalized for OSAHS from January, 2014 to December, 2014. All the cases were divided into OSAHS group and OSAHS combined with ADHD group, according to the presence or absence of ADHD. Patient's general conditions (gender, age, height, weight, allergic rhinitis history, tonsil grade and adenoid grade), OSA-18 quality of life score, intention-hyperactivity score, polysomnography parameter (apnea hypopnea index, lowest oxygen) were collected as variables. SPSS20.0 was used to perform statistical analyses. Results　There were 437 cases in this research, 298 of them were males, and 139 of them were females. Of 437 patients, 147 had OSAHS combined with ADHD (33.64%).  Higher apnea hypopnea index (P < 0.01) and severer oxygen deficiency (P < 0.01) were found in OSAHS combined with ADHD group than those in OSAHA group. Five projects of OSA - 18 score of in OSAHS combined with ADHD group were all higher than those in OSAHS group (P < 0.01). Conclusions　The incidence of pediatric OSAHS combined with ADHD in this research was more than 30%. More OSAHS combined with ADHD were found in male children. The quality of life was lower in pediatric OSAHS combined with ADHD. Oxygen deficiency was suggested to be the most important risk factor of ADHD in pediatric OSAHS.