The invention, which belongs to the technology fields including image processing as well as video coding and decoding and the like, discloses a bilinear two-fold upsampling method and a system thereof. In the prior art, a bilinear upsampling mode has a low efficiency. According to the method, four buffer areas are applied, wherein the four buffer areas include a first buffer area, a second bufferarea, a third buffer area, and a forth buffer area; a to-be-sampled image is input into the first buffer area; traversal is carried out on the to-be-sampled image as well as transverse pixel sampling, vertical pixel sampling and adjacent tetra-pixel sampling are respectively carried out on the to-be-sampled image; a transverse pixel sampling result is stored into the second buffer area, a vertical pixel sampling result is stored into the third buffer area and an adjacent tetra-pixel sampling result is stored into the fourth buffer area; and pixels in the four buffer areas are arranged interlacedly and then an image after the sampling is output. According to the invention, the method and the system are mainly utilized for carrying out bilinear two-fold upsampling processing on an image.