The crack control of the concrete lining for the subsea tunnel is effected by various uncertain factors such as geological condition, outward water pressure, tide action, concrete strength and the release of hydration heat etc. Because of the fuzziness for the lining crack control of the subsea tunnel, it is difficult to accuratly calculate the crack width to meet with the requirement of the limiting crack design for the structure. Based on the maximal permit crack formula issued in “Highway Tunnel Design Specifications”, the fuzziness analysis is made to the crack control reliability, the index of fuzzy reliable degrees of the lining maximal permit crack width is calculated by Monte Carlo method, and the sensitivity analysis to uncertain parameters is given to provide referance ro the design for the subsea tunnel.