The utility model relates to a current transformer secondary line encapsulation instrument, including casing (1), its characterized in that: there are one open -ended recess (8) in casing (1) central authorities, recess (8) bottom fixed mounting short circuit piece (2), it has four entrance hole (7) to open on casing (1) in the bottom of closing on recess (8), the foot of entrance hole (7) remains basically stable with the upper surface of short circuit piece (2), ensure that the threading is convenient, the middle and upper position of recess (8) is put and is inlayed mounting (3) in casing (1), four align to grid screw (4) are gone up in mounting (3), screw (5) penetrate in screw (4), crimping piece (6) are installed on screw (5) top, the business turn over vertical motion of screw (5) can be followed in crimping piece (6), a A for inciting somebody to action current transformer, B, C, N looks wire compresses tightly in order to realize the short circuit on short circuit piece (2). The utility model discloses effectively improved constructor construction factor of safety, guaranteed that construction process is up to standard.