Experimental data of investigation of the influence of outer couple weak shock waves on the laminar-turbulent transition on attachment line of swept cylinder in supersonic flow are presented. The couple of waves were generated by a two-dimensional roughness on the wall of the test section of supersonic tunnel. It was found that the laminar-turbulent transition on the attachment line of sliding cylinder followed by abrupt perturbation growth. In case of the great distance between falling of the waves on attachment line and the point of measurement the impact on transition was not observed. In case of the short distance between falling of the waves on attachment line and the point of measurement the laminar-turbulent transition was observed at lower unit Reynolds numbers
