A method for knitting a three-dimensional shoe blank (100, 200, 200', 200") by using a double-bed flat knitting machine, comprising: providing at least a first yarn on a front needle bed and a back needle bed of the double-bed flat knitting machine by skip-needle double-knitting and providing at least a second yarn on the back needle bed together to form a cast-on line (101, 201); knitting the first yarn on the front needle bed and the back needle bed continuing from the cast-on line (101, 201) by loop-transferring and skip-needle double-knitting to form an upper portion (112, 212); knitting the second yarn on the back needle bed continuing from the cast-on line (101, 201) by skip-needle single-knitting to form a front sole portion (122, 222), wherein the upper portion (112, 212) and the front sole portion (122, 222) are alternatingly knitted, and the front sole portion (122, 222) is connected to the upper portion (112, 212) to form a pocket structure; knitting continuing from the front sole portion (122, 222) on the front needle bed and the back needle bed to form a rear portion, wherein when forming the rear portion, a plurality of live stitches are preserved on the front needle bed at two sides of a rear end of the rear portion; and knitting continuing from a center of the rear end of the rear portion on the front needle bed and the back needle bed by double-knitting to form a heel portion with a predetermined number of stitches, wherein when the knitting of the heel portion reaches the predetermined number of stitches at two opposite sides of the heel portion, the back needle bed moves transversely to sequentially and respectively knit the live stitches preserved on the front needle bed at the two sides of the rear end of the rear portion together with the two opposite sides of the heel portion, so the heel portion and the rear portion are combined to form a 3D rear shoe portion with two joining lines (104a, 104b) formed between the heel portion and the rear portion on the two opposite sides of the heel portion, respectively, and the 3D shoe blank (100, 200, 200', 200") is formed as an integral knit fabric without any sewn portion among the upper portion (112, 212), the front sole portion (122, 222), the rear portion, and the heel portion. providing at least a first yarn on a front needle bed and a back needle bed of the double-bed flat knitting machine by skip-needle double-knitting and providing at least a second yarn on the back needle bed together to form a cast-on line (101, 201); knitting the first yarn on the front needle bed and the back needle bed continuing from the cast-on line (101, 201) by loop-transferring and skip-needle double-knitting to form an upper portion (112, 212); knitting the second yarn on the back needle bed continuing from the cast-on line (101, 201) by skip-needle single-knitting to form a front sole portion (122, 222), wherein the upper portion (112, 212) and the front sole portion (122, 222) are alternatingly knitted, and the front sole portion (122, 222) is connected to the upper portion (112, 212) to form a pocket structure; knitting continuing from the front sole portion (122, 222) on the front needle bed and the back needle bed to form a rear portion, wherein when forming the rear portion, a plurality of live stitches are preserved on the front needle bed at two sides of a rear end of the rear portion; and knitting continuing from a center of the rear end of the rear portion on the front needle bed and the back needle bed by double-knitting to form a heel portion with a predetermined number of stitches, wherein when the knitting of the heel portion reaches the predetermined number of stitches at two opposite sides of the heel portion, the back needle bed moves transversely to sequentially and respectively knit the live stitches preserved on the front needle bed at the two sides of the rear end of the rear portion together with the two opposite sides of the heel portion, so the heel portion and the rear portion are combined to form a 3D rear shoe portion with two joining lines (104a, 104b) formed between the heel portion and the rear portion on the two opposite sides of the heel portion, respectively, and the 3D shoe blank (100, 200, 200', 200") is formed as an integral knit fabric without any sewn portion among the upper portion (112, 212), the front sole portion (122, 222), the rear portion, and the heel portion.