The utility model belongs to the technical field of general equipment, relates to a connecting structure of an olive-shaped taper left-big right-small two-way conical thread bolt and a nut, and solves the problems of poor self-positioning and self-locking performance and the like of an existing thread. The internal thread (6) is a bidirectional conical hole (41) (non-entity space) on the inner surface of the cylindrical matrix (2), the external thread (9) is a bidirectional cone frustum body (71) (material entity) on the outer surface of the cylindrical matrix (3), and the complete unit body thread is a spiral olive-like (93) bidirectional conical body of which the left taper (95) is larger than the right taper (96), and the middle part of the spiral olive-like (93) is larger than the two ends of the spiral olive-like (93); performance mainly depends on conical surfaces and conicity of mutually-matched threaded bodies. The double-conical-surface threaded connection device has the advantages that the internal threads and the external threads form a section-by-section conical pair through a conical hole containing cone and a bidirectional conical hole (41) and a bidirectional conical table body (71) to form a threaded pair (10) until the internal cones and the external cones are in spiral conical surface sizing fit or sizing interference, so that a threaded connection function is realized.