School of Chemistry and Chemical Engineering, Anhui University, Hefei, 230039, P. R. China Manuscript received 30 August 1999, accepted 26 November 1999 The neOdymium complex with acid chrome blue K (ACBK) at pH 10 has been studiell in detail by beta-correction spectrophotometry. The cationic surfactant, cetyltrimethylammonium bromide (CTAB)· is useful for increasing the sensitivity and solubility of ligand and complex. The characteristic factors of complex are calculated, for example, complex ratio and stability constant. Results show that Nd(ACBK)3 is formed and its real not apparent molar absorptivity is the first to be determined as follows : \(\varepsilon_{Nd}^{520}\)(ACBK)3 = 5.54 x 104 dm3 mor1 cm-1 at pH 10. In addition, the cumulative stability constant of complex Nd(ACBK)3 is still computed to be 1.72 x 1016 in ionic strength 0.1 M and at temperature 15º.