Three conventional cultivars of onion JQS-1,MST-140 and Red beauty were used as materials to observe the statistical changes in the number of onion floral organs.The results showed that:(1)Normally,a single onion floret consisted of 6 stamens.However,the number of stamens decreased to 5 in lot of abnormal florets.In contrast,the number of stamens increased from 7 to 11 in part of onion flowers.The normal anthers produced abundant pollens,which were uniformly dispersed in anther.However there were a lot of pollens with irregular shape in the abnormal anthers;(2)Some flower with abnormal pistil were also observed,for example,the number of ovaries were decreased to 2 or increased to 4 or 6.Meanwhile the number of stayle was increased from 1 to 2 or 3;(3)Normal flower consisted of 6 tepals,but abnormal flower contain 5 to 10 tepals.It contains synchronous and non-synchronous types of variation in the changes of tepals and stamens number.These studies may offer some basis for the researches on diversity of floral organ development,rich the patterns of floral development and the classification and system development of plant.