∵复数z满足（3-4i）z=5i，∴z= 5i 3?4i = 5i(3+4i) (3?4i)(3+4i) = ?20+15i 25 =- 4 5 + 3 5 i，∴|z复数z|= 16 25 + 9 25 =1，故答案为：1．
