Abstract: The change of the concentration of organic compounds in coagulation bath was measured during hollow fiber spinning process by ultraviolet spectrophotometer;the relationships between the concentration of DMAC/PVP and COD were tested also.The results indicated that the relationship between the concentration of organic compound and COD is linear correlation,and between absorption and COD is also linear correlation in the range of 250～240 nm,the coefficients of correlation are r²>0.99.So the concentration of organic compound in coagulating bath of hollow fiber membrane for DMAC/PVP system can be tested by ultraviolet spectrophotometer.