It was demonstrated by oxygen equilibrium curve that the pyridoxal 5-phosphate(PLP) modified porcine deoxyhemoglobin(pHbbeta) had lower oxygen affinity than that of stroma-free porcine hemoglobin(pHb). Accourding to analysis of SDS-PAGE, the porcine hemoglobin derivatives were not cross-linked between its subunits. A conjugate was synthesized between pHbbeta and p-toluenesolfonyl chloride-actived dextran. The oxygen affinity of Dx-pHbbeta was high than that of pHbbeta, but still lower than that of pHb. Judged by cellulose acetate film electrophoresis, the mobility of Dx-pHbbeta was apparently different from that of pHbbeta. Dx-pHbbeta has characterized absorbance peak in UV spectrum, which can be used to analysis the binding ratio between Dx and pHbbeta.