Abstract: At present great varieties of raticide drugs are available in domestic. For example diphacinone or bromadiolone are high poisonous,slow effect raticide, these compounds will cause the viscera haemorrhage unceasing to death. It is often happened mistaken and being used for murder. So it is necessary to develop an effectivet, accurate and confirm method which will provide evidence to solve these cases in the forensic field. -MS/MS technique provide not only high sensitivity, strong confirmation but also can make accurate quantity determination. This file reports a MS/MS method for analyzing simaltaneously naphthylthoiurea and diphacinone by Varian 1 200 L LC-MS/MS and achieved very satisfied result.