Abstract: In the South China Sea, the high flowrate marine environment may affect initial opening of semi-submersible drilling platform considerably. In order to decrease the costly expense of marine drilling, operators are urgently in need of a technique to cope with the problem of high flowrate. This paper introduces a new method of guarding against inclination in surface level of semi-submersible platform in high flowrate marine environment. By using this method, operators can spud in normally when the flowrate is very high. As a result the collaring time for waiting low flowrate could not be delayed any longer. The successful application of this method in YingGe sea indicates that it is assured and could reduce the time and cost of well construction effectively.