The utility model provides a small -size optic fibre, the glass part and the outside even deposited coat of glass part that are 125 mu m including the external diameter, the coat external diameter is 200 mu m. The coat includes the outer coat in the interior coat and the interior coat outside. Interior coat external diameter is 160 mu m. The glass part is formed by the G657A2 fiber drawing. The utility model discloses a G657A2 fiber drawing becomes the glass part, and it can still keep excellent bending property under the condition that by a wide margin reduces coating thickness. Through the coating of adoption low modulus and suitable inside and outside coating thickness proportion, make 200 mu m's small -size optic fibre's machinery and environmental performance also can satisfy relevant standard requirement completely. Adopt the utility model discloses an optical cable diameter of small -size optic fibre production reduces above 10%, and the optic fibre capacity improves 40%, can fully improve the interior optic fibre core number of unit cross -sectional area, reduces the optical cable laid down cost, practices thrift pipeline space resources.