Abstract: A protecting cover for a bicycle control line includes an inner capsule and an outer capsule covering the control lines in a same section of a bicycle body. The inner capsule is made of a hard plastic material and in a hollow passage form, and has a plurality of protrusions disposed on an external circumferential surface of the inner capsule. The outer capsule is made of a soft material and in a hollow passage form and has a plurality of penetrating holes disposed at positions corresponding to the protrusions on an external circumferential surface of the inner capsule. The inner capsule covers a section of brake or speed change control lines in contact with the bicycle body. The flexible outer capsule covers the inner capsule, and the protrusions at the external surface of the inner capsule are embedded into the penetrating hole of the outer capsule, so as to protect the bicycle body from being scratched or damaged by the contact of the control line.