Hyacinth cultivar ‘Pink Pearl’ root tips were pretreated with five reagents including colchicine,8-hydroxyquinoline,cycloheximide,mixture of colchicine and 8-hydroxyquinoline and ice-water mixture by different time grads to obtain well dispersed chromosome.These results laid a foundation for the hyacinth chromosome analysis and fine structure researches.The results showed that after fixed with Carnoy fixative I,dissociated,dyed,squashed,the root tips pretreated with these 5 reagents all could be used in chromosomes preparation,which the chromosomes spreader well,given a normal form,and were easy for counting and karyotype analysis.The most favorable treated time for colchicine and 8-hydroxyquinoline was 12 h and 20 h,respectively;and for the other three reagents cycloheximide,mixture of colchicine and 8-hydroxyquinoline and ice-water mixture,the most favorable treated time was all 24 h.Hyacinth karyotype analysis was carried out with chromosome from root tip cells.The result showed that the karyotype formula was 2n=2x=16=6m+4sm+2sm^sat+4st.The asymmetry index was 60.2% and belonged to category 2C of Stebbins.