The invention discloses a fixing mechanism for vertical lighting of a xenon lamp. The fixing mechanism comprises an anode electrode holder, an anode supporting rod, an anode supporting rod seat, a support, a cathode electrode holder, a cathode supporting rod and a cathode supporting rod seat. The left end of the anode supporting rod is horizontally connected with the anode electrode holder. The right end of the anode supporting rod is fixed to the upper end of the support through the anode supporting rod seat. The anode electrode holder can vertically move relative to the anode supporting rod. The anode supporting rod can rotate in the anode supporting rod seat. The left end of the cathode supporting rod is horizontally connected with the cathode electrode holder. The right end of the cathode supporting rod is fixed to the lower end of the support through the cathode supporting rod seat. The cathode supporting rod can rotate in the cathode supporting rod seat. According to the fixing mechanism, vertically downward lighting of the xenon lamp can be achieved, and vertically upward lighting and horizontal lighting of the xenon lamp can also be achieved; and the transportability of a xenon lamp system is improved, and the reliability and safety of the xenon lamp system are improved. The invention further discloses a fixing method for vertical lighting of the xenon lamp. The method has all the beneficial effects of the mechanism.