The utility model discloses a dismantled and assembled barrel endoscope. It is by objective part, biography like part, eyepiece triplex, a plano -concave lens is installed including a body to the objective part on the anterior inner wall of a body, be provided with under the plano -concave lens to be located the triangular lens on the body axial lead no. One, and the rear of triangular lens has set gradually plano -convex lens, cemented doublet, the biography includes no. Two bodys like the part, has two symmetrical excellent lens that set up in no. Two bodys, the eyepiece part sets up three contact lenss including a cuff section of thick bamboo in the telescopic inner tube, set up plano -convex lens in the telescopic urceolus, objective part, biography connect gradually whole of formation like part and eyepiece part. After adopting foretell structure, its simple structure, convenient to carry surveys the effect very good, and the suitability is strong, is suitable for army, policeman and shooting range very much and carries out the maintenance maintenance of all kinds of gun and use, consequently has great popularization and application and worth.