The invention provides a die for winding and casting a rectangular dry-changing epoxy coil and a production method; the die comprise a core die which is used for winding wires, an outer die which is positioned at the outside of the core die and used for casting, and a pressing mechanism. The core die comprises a rectangular half cylinder which is formed by docking two half bending-processed steel plates through a core die connection mechanism at the open end, and a plurality of supporting plates which are used as the support of the core die and arranged with certain spacing. The pressing mechanism is composed of two parallel arranged horizontal plates and a vertical plate which is fixed at the middle of the two horizontal plates in a criss-cross way. The production method of the die for winding and casting a rectangular dry-changing epoxy coil comprises the following steps: making a lower location ring and an upper location ring; calculating the sizes of the outer die and the core die; cutting the outer die and the core die, flanging, heat treatment, pressing guiding angles, sealing angles, knocking strengthening ribs, processing supporting plates, processing a pressing mechanism and assembling. The core die with the assembling structure of two half cylinder bodies adopted in the invention is easy to remove. Furthermore, the press mechanism has good sealing performance and convenient using.