Abstract: Basic data useful for the resolution of DL-threo-1-p-nitrophenyl-2-amino-1, 3-propanediol with tartaric acid were studied. Pure samples of D- and L-threo-1-p-nitrophenyl-2-amino-1, 3-propanediol, their bitartrates and normal tartrates were prepared and their physical constants determined (Table 1). Mixed melting point curve of D- and L-threo-1-p-nitro-phenyl-2-amino-1, 3-propanediol (Fig. 1) indicated the presence of a racemic compound as evidenced by a shortening of the melting range at 1:1 composition. Indeed, solubilities of the DL- compound and its optically active components in water also differred (Fig. 2). Solubility curves of the different bitartrates and normal tartrates in methanol and the bitartrates in water were shown in Fig. 3 to Fig. 5 respectively. Based upon these data, procedures for resolution through the bitartrates were suggested, using either water or methanol as solvent. However, as a consequence of greater solubility, the procedure using water as solvent called for an extraction temperature of only 15℃ above that of room temperature, and the mother liquor should be recycled after being cooled to separate the L-threo-1-p-nitrophenyl-2-amino-1, 3-propanediol bitartrate.