The anti-rolling stability,failure process and critical velocity of 4 commonly applied concrete interlocking blocks are tested and analyzed by physical model tests,Fluent-2D calculation and force tests.The influence of water depth and location (at the edge,lap joint,or middle of the bed-protection mattress) on the block’s anti-rolling stability is also studied.A modification of the formula in the current specification is proposed,involving water depth,block structure and location.Then,3 new-type blocks are designed and compared with the commonly used block.The results show that the anti-rolling stability of the 3 new-type blocks is certainly better than that of the commonly used 4.