Sodium alginate containing quarternary ammonium group(QSA) was synthesized by the reaction of sodium alginate(SA) and [3-(methacryloylamino) propyl]trimethyl ammonium chloride(APTAC) using potassium presulfate(KPS) as initiator. The nitrogen content of synthesized QSA was 3.3%, i.e. 0.3 mol of APTAC per a mole of uronic acid unit, and this was also confirmed by FT-IR analysis. The SA/QSA blend fibers having various nitorgen contents were produced by a wet spinning process using aqueous $CaCl_{2}$ solution as a coagulant. The blend fibers whose nitrogen content was greater than 1% showed excellent antimicrobial activity. The effect of blending and spinning conditions on mechanical and structural properties were investigated. The tenacity and initial modulus of blend fibers decreased with increasing QSA content. From wide-angle X-ray diffraction and scanning electron microscopy, it was observed that the crystal structure of SA/QSA blend fiber was slightly different from that of SA and the cross-sectional structure of the blend fiber appeared to be more compact than that of alginate fiber.