Abstract: Offshore platforms operating in harsh environments often suffer from severe wave impact loads which threaten the structural integrity and staff's safety. In this paper, wave impact loads on a semi-submersible drilling platform are studied experimentally. Measurement units were designed specially to monitor wave impact loads. According to the experimental datum, sensitivity of wave impact loads with respect to wave headings and the spatial distributions of wave impact loads were systematically analyzed. The results show that the platform under the beam seas and head seas is exposed to more serious wave impacts than oblique seas. Wave impact loads mainly concentrate on some area above the waterline and show obvious three-dimensional effect.