A novel method, incompletely suppressed conductometric detection, has been developed for the determination of anions of very weak acids. The principle of the method is discussed. The advantages of the method over the suppressed and nonsupressed methods for the determination of anions of very weak acids are also discussed theoretically. Results showed that the detection limits of the method for arsenous acid and boric acid were lower than those of nonsuppressed conductometric method. Being compared with suppressed conductometric method, the sensitivity was improved greatly. For 250 mg/L boric acid, 261- and 1002-fold increases in peak height and peak area were obtained, respectively. Within the linear range of the detection, the linear correlation coefficients of the peak areas of two weak acids were 0.9991 and 0.9985, respectively.