Soluble form of human urokinase receptor was cloned into Drosophila Schneider 2 secretion expression vector pMT/Bip/v5-his, and co-transfected with pCoHygro into S2 cells, to establish stably S2 cells line. The expressed suPAR from such procedure tends to form oligomer and is unstable, presenting difficulties for its structural studies. Here a purification procedure that yields monomeric suPAR was reported. SuPAR obtained through such procedure is monomeric and quite stable. SuPAR complex with amino terminal fragment (ATF) of uPA and an anti-suPAR antibody (ATN615) was crystallized by dialysis method into diffracting crystals (1.9 Å).