Abstract: Using surface spreading-silver staining technique,the synaptonemal complexes (SCs) in spermatocytes of the tree shrew were observed by electron microscopy.It is shown that the mean relative lengths and centromeric indices of autosomal SCs agree closely with those of mitotic chromosomes.Comparisions of the morphology and the pairing of sex chromosomes during meiotic prophase between the tree shrew and other primates are made and discussed in this paper.