Abstract:The number and karyotype of Albizzia julibrissin chromosome is researched,applying fingertip pressing flake method.The formula for Karyotype is reported in this paper.which is 2n=26=18m+6sm+2st and belongs to the type of “2B”.The number of A.julibrissin cell chromosome is 2n=26.The relative length of chromosome is 2n=26=4L+8M2+12M1+2S.The chromosomal characteristics prove that the A.julibrissin belongs to more advanced species.