A method for estimating an onset time of an infarct region based on brain images, the method comprising: obtaining pre-acquired brain images; extracting from the infarct region included in the brain images a set of quantitative values that vary according to the onset time of the infarct region; and determining the onset time of the infarct region based on the extracted set of quantitative values by applying a corresponding relation prepared therefor, wherein the corresponding relation is prepared using a classifier that classifies the set of quantitative values by the onset time of the infarct region, characterized in that obtaining the brain images comprises: generating a MRI-based DWI image, an ADC image, a PWI image, a FLAIR image, a T1 image, a T2 image and a GRE image, the method further comprises: after obtaining the brain images and before extracting the set of quantitative values, segmenting the infarct region using the DWI or ADC image; segmenting a penumbra region of the infarct region using the PWI image; and registering the brain images that include the DWI or ADC image with the segmented infarct region and the PWI image having the segmented penumbra region; extracting the set of quantitative values further comprises: acquiring from the registered brain images two or more quantitative values selected from the group consisting of an infarct volume V I, an infarct location V IL, a penumbra volume Vp, a penumbra position V PL, mismatch M between an infarct region and a penumbra region, an average intensity of the infarct region in each brain image DI DWI, DI ADC, DI FLAIR, DI T1, DI T2, and an average intensity of the penumbra region in each brain image DP DWI, DP ADC, DP FLAIR, DP T1, DP T2. obtaining pre-acquired brain images; extracting from the infarct region included in the brain images a set of quantitative values that vary according to the onset time of the infarct region; and determining the onset time of the infarct region based on the extracted set of quantitative values by applying a corresponding relation prepared therefor, wherein the corresponding relation is prepared using a classifier that classifies the set of quantitative values by the onset time of the infarct region, characterized in that obtaining the brain images comprises: generating a MRI-based DWI image, an ADC image, a PWI image, a FLAIR image, a T1 image, a T2 image and a GRE image, the method further comprises: after obtaining the brain images and before extracting the set of quantitative values, segmenting the infarct region using the DWI or ADC image; segmenting a penumbra region of the infarct region using the PWI image; and registering the brain images that include the DWI or ADC image with the segmented infarct region and the PWI image having the segmented penumbra region; extracting the set of quantitative values further comprises: acquiring from the registered brain images two or more quantitative values selected from the group consisting of an infarct volume V I, an infarct location V IL, a penumbra volume Vp, a penumbra position V PL, mismatch M between an infarct region and a penumbra region, an average intensity of the infarct region in each brain image DI DWI, DI ADC, DI FLAIR, DI T1, DI T2, and an average intensity of the penumbra region in each brain image DP DWI, DP ADC, DP FLAIR, DP T1, DP T2. after obtaining the brain images and before extracting the set of quantitative values, segmenting the infarct region using the DWI or ADC image; segmenting a penumbra region of the infarct region using the PWI image; and registering the brain images that include the DWI or ADC image with the segmented infarct region and the PWI image having the segmented penumbra region; extracting the set of quantitative values further comprises: acquiring from the registered brain images two or more quantitative values selected from the group consisting of an infarct volume V I, an infarct location V IL, a penumbra volume Vp, a penumbra position V PL, mismatch M between an infarct region and a penumbra region, an average intensity of the infarct region in each brain image DI DWI, DI ADC, DI FLAIR, DI T1, DI T2, and an average intensity of the penumbra region in each brain image DP DWI, DP ADC, DP FLAIR, DP T1, DP T2.