A resonant high current density transformer comprising: two cores, each including first and second side posts (11, 12) extending in the same direction from two sides thereof, wherein the two cores abut against each other with the two first side posts facing each other and the two second side posts facing each other; a first bobbin provided with a penetrating first through-hole that envelops the first side posts on the same side of the two cores, wherein a side plate is provided on the outer periphery of either end of the first through-hole, and a spacer is provided on the first bobbin between the two side plates on the outer periphery of the first through-hole, and two coil slots are formed on the two sides of the spacer, respectively; a primary winding formed by winding wires around the two coil slots of the first bobbin; a second bobbin provided with a penetrating second through-hole that envelops the second side posts on the same side of the two cores, wherein the second bobbin is provided with a spacer on the mid-section of the outer periphery of the second through-hole, and two winding regions (43, 431) are formed on the two sides of the spacer, respectively; two metal plates (6, 60) bent to envelop the outer peripheries of the winding regions (43, 431) of the second bobbin to form a secondary winding; a bobbin mount disposed at the external flank of the second bobbin, the bobbin mount including a base provided with a barrier plate on a side closer to the first bobbin, wherein the barrier plate is used for separating the first and second bobbins; characterized in that an insulating "U-shape" separating cover is provided on a side of the first bobbin closer to the bobbin mount, wherein the two ends of the separating cover cover the top and bottom sides of the first bobbin, respectively. two cores, each including first and second side posts (11, 12) extending in the same direction from two sides thereof, wherein the two cores abut against each other with the two first side posts facing each other and the two second side posts facing each other; a first bobbin provided with a penetrating first through-hole that envelops the first side posts on the same side of the two cores, wherein a side plate is provided on the outer periphery of either end of the first through-hole, and a spacer is provided on the first bobbin between the two side plates on the outer periphery of the first through-hole, and two coil slots are formed on the two sides of the spacer, respectively; a primary winding formed by winding wires around the two coil slots of the first bobbin; a second bobbin provided with a penetrating second through-hole that envelops the second side posts on the same side of the two cores, wherein the second bobbin is provided with a spacer on the mid-section of the outer periphery of the second through-hole, and two winding regions (43, 431) are formed on the two sides of the spacer, respectively; two metal plates (6, 60) bent to envelop the outer peripheries of the winding regions (43, 431) of the second bobbin to form a secondary winding; a bobbin mount disposed at the external flank of the second bobbin, the bobbin mount including a base provided with a barrier plate on a side closer to the first bobbin, wherein the barrier plate is used for separating the first and second bobbins; characterized in that an insulating "U-shape" separating cover is provided on a side of the first bobbin closer to the bobbin mount, wherein the two ends of the separating cover cover the top and bottom sides of the first bobbin, respectively.