The invention belongs to the field of drug detection, and particularly relates to a method and a kit for detecting five psychotropic drugs and main metabolites thereof in blood. The five psychotropicdrugs and the main metabolites thereof comprise: olanzapine and demethyl olanzapine, risperidone and 9-hydroxy risperidone, aripiprazole and dehydrogenated aripiprazole, Escitalopram and demethyl citalopram, sertraline and N-demethyl sertraline. Accoridng to the method provided by the invention, a pair of quantitative ion pairs is respectively selected for each detection substance, a relative retention time thereof is used as a qualitative basis, and a standard curve is made by using a standard product for quantification; furthermore, the accuracy and effectiveness of the method are evaluatedfrom quality control of three low, middle and high levels, thereby avoiding distortion of the detection result; and meanwhile, an internal standard working solution is applied to correction, so that matrix effects can be avoided, and accurate quantification is realized. The method provided by the invention has the advantages of simple and rapid operation, high flux and low cost, and can be appliedto the therapeutic drug monitoring of the psychotropic drugs in the clinical work of the psychiatry department.