Objective To resolve the problem that qualified chloramine T was difficult to purchase for some basic laboratories Methods Using the solution of available chlorine prepared by bleaching power instead of chloramine T, the method for determination of cyanide in drinking water was improved Results The data obtained by this assay accorded with Beers Law in the range of 0～2 0 ?g/25 ml cyanide The detection limit,relative standard deviation,and recovery rate were 0 04?g,2 69%～3 09% and 97 50%～99 17% respectively Conclusion This method for determination of cyanide in drinking water was simple and easy to operate and presented good precision and accuracy