ObjectiveTo analysis the causes of infant spasm (IS) and provide a theoretical basis for clinical diagnosis and treatment. MethodsCollected the clinical data of 116 IS cases in our hospital from May 2011 to December 2013, which conform to the diagnostic standard, and analysis its causes. ResultsIn the116 cases we collected, symptomatic IS is primarily for 78 cases (67.24%); the onset age of symptomatic IS within 6 months was 76.39% (55/72), higher than the rates of symptomatic IS beyond 6 months 52.27% (23/44) (P=0.007); The pathogenic factor in symptomatic IS, prenatal accounted for 48.72%, intrapartum factors accounted for 34.62%; for sexually transmitted diseases accounted for 47.44%, venereal disease accounted for 52.56%. In 78 cases of symptomatic IS, gender has no relation with its pathogenic factors; the onset age within 6 months of antepartum and intrapartum factor is significantly higher than the rates of symptomatic IS beyond 6 months (89.09% VS 69.57%); distribution between urban and rural areas and its pathogenic factors is related, prenatal factors of urban IS significantly lower than which in rural areas (38.30% VS 64.51%), intrapartum factor IS significantly higher than the rural IS (44.68% VS 19.35%). ConclusionThe cause of the IS given priority to with symptomatic, IS in the majority with, and prenatal or developmental factors in the higher flight in symptomatic, and the smaller of the onset age antepartum and intrapartum factor becomes more apparent, prenatal factors in the rural areas is higher than which in the unban areas, but intrapartum factor in the unban areas is higher than which in the rural areas. Magnetic resonance imaging (MRI) still plays an important role in etiology diagnosis.