Instead of plat-and-frame filtration,separation processes with ultrafiltration(UF) and nanofiltration(NF) were introduced to purify and concentrate the tylosin broth.After comparing several membranes with different materials and molecular weight cut-off,PES-150 and DL2540 were found to be the optimum UF and NF membranes.With the pretreatment of tylosin fermentation by using diatomite and additive 250L de-ionized water,flux of UF would increase 82%.Meanwhile,yield coefficient of tylosin was almost 97%.Purities of each component of tylosin of UF and plat-and-frame filtrate were almost same.The yield coefficient of tylosin in extraction of UF filtrate increased 20%~26%.NF concentrated the UF filtrate with concentration multiples 3.5 and flux was 41.3 L/(m2·h).The yield coefficient of tylosin of NF was 99%.The color of extract phase of concentrated solution of NF,which without emulsification,was lighter than the ones without UF-NF.