The successful boulder prospecting by means of marine seismic reflection CDP stacking technology adopted in the construction of the waterintake tunnel of Taishan Nuclear Power Station is analyzed, so as to reduce the construction risk of shieldbored tunnel in bouldercontaining strata. The practice demonstrates that the geophysical prospecting technology adopted is feasible for prospecting boulders under water, especially for the detection of boulders with diameter being larger than 1 m.