Laser polishing technique using thermal effect of the interaction of light with matter to achieve removal of material,it is a non-contact polishing techniques.In recent years,ultrafast laser polishing techniques got great progress,when ultrafast laser-matter interaction,no thermal effect or thermal effect is very small,the removal of material is achieved primarily through momentum transfer.In the material removal process will appear the phenomenon of surface atoms in the redistribution,using this effect,we are likely to achieve the manufacture of the ultra-smooth surface of atomic-scale magnitude.This article has discussed and analyzed the mechanism of ultrafast laser semiconductor materials,based on this,parameters and their influence on the influence of ultrafast laser polished monocrystalline-silicon effects were studied.Used the orthogonal experiment method to optimize the main parameters of the laser polishing,it can reach to a better combination of optimized parameter values.Used self-built picosecond laser polishing system and did monocrystalline-silicon polishing experiment,got a good polishing effect.