Abstract: A model and an application thereof, the model being used for detecting a benign and malignant degree of a tumor. The model grades a change of an imprinted gene in a tumor by calculating a deletion expression quantity of the imprinted gene and a copy number abnormal expression quantity of the imprinted gene. The detection model and device in the present invention presents the expression of loss of imprinting in a sample of a tumor patient in a direct way for the first time; based on an imprinted gene in situ labeling method, a change of an imprinted gene is detected objectively, directly, early, and precisely, and a quantitative model can be provided, to make a great contribution to molecular pathology diagnosis.