The invention provides geological cement for solidification of radioactive incineration ash and a solidification method of the radioactive incineration ash. According to the solidification method of the radioactive incineration ash, slag containing aluminum silicate and an adsorbent are evenly mixed to prepare an A material of the geological cement, a composite liquid exciting agent is used for preparing a B material of the geological cement, the A material of the geological cement, the B material of the geological cement and the radioactive incineration ash are stirred in an agitator kettle for five minutes after water is added to the A material of the geological cement, the B material of the geological cement and the radioactive incineration ash, and then the mixture is moved into a die, so that forming and maintaining are achieved. According to the solidification method of the radioactive incineration ash, the waste tolerance can be improved greatly, the fluidity of a solidified body ranges from 150 mm to 180 mm, the fluidity is high, adjustment is available, the final setting time is shorter than twelve hours, and proper initial setting time is guaranteed for solidification. After maintenance is conducted for 28 days, the compressive strength of the solidified body reaches over 20 Mpa, freezing and thawing cycle testing is conducted twenty times, the compressive strength loss of a sample is smaller than 10%, soaking testing is conducted for 90 days, no crack exists on the surface of the solidified body, the compressive strength is in the rising tendency, and the leaching rate of the <137> Cs element on the forty-second day is 4.4*10<-4> m/d.