The invention relates to an integrated high-voltage electrical box for a battery system. The integrated high-voltage electrical box comprises an upper cover and a casing, wherein the upper cover covers the casing and is detachably connected with the casing; a high-voltage component, a positive and negative electrode input copper bar and two positive and negative electrode output copper bars are mounted in the casing, one end of the positive and negative electrode input copper bar and one end of each of the two positive and negative electrode output copper bars are connected with the high-voltage component, and the other end of the positive and negative electrode input copper bar and the other end of each of the two positive and negative electrode output copper bars are located in the upper side edge position of the casing; a plugging structure which is used for enabling the other ends of the two positive and negative electrode output copper bars and the other end of the positive and negative electrode input copper bar to be safely exposed is arranged on the peripheral side of the upper cover. One input end and two output ends are arranged on a battery case, so that the electrical box has higher compatibility and can adapt to different project demands; the high-voltage component is mounted on the casing, so that the electrical elements are high in integration degree, high in space utilization rate and flexible and convenient to maintain; the plugging structure is arranged on the upper cover, and the high voltage input and output safety of the electrical box is improved.