Abstract: The concrete cracks on railway bridges are common problems ,which have serious impact on the service life of the railway bridge .A non-equal interval GM (1 ,1) prediction model based on grey system theory is proposed to pre-dict the crack width of the railway concrete bridge .According to the predicted deterioration of bridge conditions ,the ma-intenance plan of BICS can be developed to improve the bridge conditions and train safety .The prediction model was vali-dated by using the crack data of Beiniuchuan Super-large Bridge of Shenshuo Railway from 1996 to 2012 .The results show that the prediction model can accurately predict the crack width of the bridge .The paper also analyzes the effect of BICS injection method applied in Beiniuchuan Super-large Bridge of Shenshuo Railway .Its repair effect on the concrete crack is significant .