A locking and insertion structure, applicable for an electronic device including a casing, includes a fastening element and a locking element. The casing includes a bottom part, a locking seat and a cantilever part. The fastening element includes a body disposed on the casing, a first locking part extending from the second locking part to between the cantilever part and the locking seat, and a second locking part extending from the body onto the cantilever part. The cantilever part is between the first and second locking part. A first locking hole of the first locking part, a second locking hole of the second locking part and a third locking hole of the cantilever part align with each other. The locking element penetrates through the second, third and first locking hole and is inserted into the locking seat sequentially so the fastening element is affixed to the casing.