The invention discloses an internal coil fixing structure of a pulse transformer. The structure comprises a bottom plate. The upper surface of the bottom plate is fixedly connected with a first fixingblock. A concave hole is formed in the right side face of the first fixing block. A coil panel is arranged above the bottom plate, the left end of the coil panel extends into the concave hole, and the left end of the coil panel is fixedly connected with a connecting plate. Sliding plates are fixedly connected to the upper surface of the connecting plate and the bottom surface of the connecting plate. The side faces, away from each other, of the two sliding plates are in contact with the inner side wall of the concave hole. A second fixing block is placed on the upper surface of the bottom plate. A clamping groove is formed in the left side face of the second fixing block. An insulating plate is fixedly connected to the right end of the coil panel. The coil panel can be conveniently installed and fixed, inconvenience of fixing of the internal coil of the pulse transformer is avoided, and the internal coil can be fixed more conveniently. The internal coil fixing structure is mainly applied to the technical field of pulse transformers.