The invention discloses technology for calcining plaster plates by using 10 to 20 percent of chromium slag, and 60 to 70 percent of alkali slag at high temperature of between 1,250 and 1,450 DEG C in a vertical kiln and belongs to treatment and comprehensive utilization technology of chromium slag. The technology comprises: mixing 10 to 20 percent of the chromium slag, and 60 to 70 percent of the alkali slag with coal and clay; evenly mixing, pulverizing, pelletizing and calcining the mixture; and adopting the high-temperature environment of between 1,250 and 1,450 DEG C and carbonic oxide in the vertical kiln to reduce hexavalent chromium in the chromium slag into trivalent chromium, so as to further achieve the aims of detoxification, comprehensive utilization of firing materials, no secondary pollution, high treatment speed, low cost and reduction of the construction cost.