A depth image denoising method, wherein the method comprises the following steps: a step S110 of, decomposing an original depth image of a shot object into n layers of depth image (M1∼Mn), where n is an integer that is greater than or equal to four, wherein each layer of depth image corresponds respectively to a different depth interval; a step S120 of, denoising on each of the n layers of depth image (M1∼Mn), to eliminate at least one isolated noise region in each of the n layers of depth image (M1∼Mn); and a step S130 of, merging the denoised n layers of depth image (M1∼Mn), to obtain a final denoised depth image, wherein, the step S110 further comprises the following steps: a step S111 of, obtaining an actual distance region [Y2, Y1] that corresponds to a preset depth region [X1, X2] of the original depth image, in accordance with a corresponding relation between a depth (x) of the original depth image and an actual distance (y) of the shot object to a visual imaging apparatus; a step S1 12 of, dividing equally the actual distance region [Y2, Y1] that corresponds to the preset depth region [X1, X2] of the original depth image into n distance intervals (B1∼Bn); a step S113 of, dividing the preset depth region [X1, X2] of the original depth image into n depth intervals (A1∼An) which correspond respectively to the n distance intervals (B1∼Bn); and a step S114 of, decomposing the original depth image into the n layers of depth image (M1∼Mn) which correspond respectively to the n depth intervals (A1∼An); wherein interval lengths of the four distance intervals (B1∼Bn) are equal to one another, interval lengths of the n depth intervals (A1∼An) are not equal, and interval lengths of the n depth intervals (A1∼An) are increased in turn. a step S110 of, decomposing an original depth image of a shot object into n layers of depth image (M1∼Mn), where n is an integer that is greater than or equal to four, wherein each layer of depth image corresponds respectively to a different depth interval; a step S120 of, denoising on each of the n layers of depth image (M1∼Mn), to eliminate at least one isolated noise region in each of the n layers of depth image (M1∼Mn); and a step S130 of, merging the denoised n layers of depth image (M1∼Mn), to obtain a final denoised depth image, wherein, the step S110 further comprises the following steps: a step S111 of, obtaining an actual distance region [Y2, Y1] that corresponds to a preset depth region [X1, X2] of the original depth image, in accordance with a corresponding relation between a depth (x) of the original depth image and an actual distance (y) of the shot object to a visual imaging apparatus; a step S1 12 of, dividing equally the actual distance region [Y2, Y1] that corresponds to the preset depth region [X1, X2] of the original depth image into n distance intervals (B1∼Bn); a step S113 of, dividing the preset depth region [X1, X2] of the original depth image into n depth intervals (A1∼An) which correspond respectively to the n distance intervals (B1∼Bn); and a step S114 of, decomposing the original depth image into the n layers of depth image (M1∼Mn) which correspond respectively to the n depth intervals (A1∼An); wherein interval lengths of the four distance intervals (B1∼Bn) are equal to one another, interval lengths of the n depth intervals (A1∼An) are not equal, and interval lengths of the n depth intervals (A1∼An) are increased in turn. a step S111 of, obtaining an actual distance region [Y2, Y1] that corresponds to a preset depth region [X1, X2] of the original depth image, in accordance with a corresponding relation between a depth (x) of the original depth image and an actual distance (y) of the shot object to a visual imaging apparatus; a step S1 12 of, dividing equally the actual distance region [Y2, Y1] that corresponds to the preset depth region [X1, X2] of the original depth image into n distance intervals (B1∼Bn); a step S113 of, dividing the preset depth region [X1, X2] of the original depth image into n depth intervals (A1∼An) which correspond respectively to the n distance intervals (B1∼Bn); and a step S114 of, decomposing the original depth image into the n layers of depth image (M1∼Mn) which correspond respectively to the n depth intervals (A1∼An); wherein interval lengths of the four distance intervals (B1∼Bn) are equal to one another, interval lengths of the n depth intervals (A1∼An) are not equal, and interval lengths of the n depth intervals (A1∼An) are increased in turn.