We　present　a　technology　of　ultrafast　imaging　using　femtosecond　laser　as　probe　light　and　ICCD　camera　as　imaging　instrument.　And　we　obtained　time-resolved　ICCD　images　of　a　single　nanosecond　laser　pulse　(30ns　laser　pulse　with　a　wavelength　of　1064nm)　ablation　of　silicon　surface　taking　advantage　of　this　technology.　This　research　shows　that　when　a　single　nanosecond　laser　pulse　was　focused　onto　the　silicon　target,　it　induced　plasma　firstly.　The　produced　plasma　was　very　much　and　its　propagation　was　very　fast　at　first.　And　when　the　nanosecond　laser　pulse　passed,　the　amount　and　propagation　of　the　plasma　didn＇t　increase　any　more　until　it　disappeared.