An exposure device for accessing a paraspinal muscle space with a small posterior spinal incision, comprising: a lateral spine plate retractor of the spinous process and an outer lateral retractor of the co-operating vertebral plate, in which the spinal plate retractor lateral of the spinous process consists of a first handle (1) and a first body of the retractor, the first body of the retractor is an L-shaped metal bar, one end of the first body of the retractor is fixedly connected to the distal end of the first handle (1), the other distal end of the first retractor is curved towards the direction of the first handle (1) and this end is provided with a horizontal toothed part (4) along the width direction of the first body of the retractor ； wherein the horizontal toothed part (4) located on one side of the other end of the first retractor body is directed towards the first handle (1), and an angle formed between the horizontal toothed part (4) and the end is an angle obtuse； wherein the first body of the retractor comprises a first horizontal segment (2) and a first vertical segment (3), in which an angle of 80 ± 10 degrees is formed between the first horizontal segment (2) and the first vertical segment (3), an angle of 165 ± 15 degrees is formed between the first handle (1) and the first horizontal segment (2), the first handle is located on one side of the first horizontal segment (2) opposite the first vertical segment ( 3), and the other distal end of the first body of the retractor is curved at 10 ± 10 degrees towards the direction of the first handle (1)； The outer side retractor of the vertebral plate consists of a second handle (5) and a second body of the retractor, the second body of the retractor is an L-shaped metal bar, one end of the second body of the retractor is connected to the distal end of the second handle (5), and the other distal end of the second body of the retractor is provided with a linguiform protrusion form (8) that curves in a dir
