The invention provides a method and device for identifying tumor loads in samples, and particularly provides a method for identifying tumor loads in the samples in a non-diagnostic mode. The method comprises the steps that 1, a sample to be tested is provided; 2, sequencing is performed on the sample to be tested, and therefore a genome sequence of the sample is obtained; 3, the genome sequence obtained in the step 2 is compared with a reference genome, and therefore position information of the genome sequence on the reference genome is obtained; 4, the reference genome is divided into M region fragments, wherein each region fragment is a window b, and a copying number of each window b is calculated; 5, each window b in the step 4 is subjected to Z testing, so that a Z value of each window b is calculated; 6, according to the Z value obtained in the step 5, GAS is calculated, and tumor loads in the sample to be tested are identified on the basis of the value of GAS. According to the method and system, sensitivity and universality of tumor detection can be improved.