Monitoring results show that serious uplifting and dislocation occur to the segment lining of No. 1 water division tunnel of Taishan nuclear plant. In the paper, the influences of waterreducing agents, polypropylene fibre and flocculation agent on the grout for simultaneous grouting in shield tunneling are studied by means of optimization design and grout mixing proportion tests. Highperformance grout for simultaneous grouting that can reduce the uplifting of the segment lining is prepared and applied in the works. In the end, the uplifting of the segment lining is reduced, the quality of the segment lining is improved and the water seepage from the shield tail is well controled.