Laser-induced chemical etching of the InP (100) surface with a chlorinemolecular is investigated using a Nd: YAG laser at 1064 um. The mass and velocitydistributions Of reaction Products at different surface temperatures (290 K and 560 K) are determined by the time-resolved mass spectrometry. Both laser fluence and the normalcomponent of the incident Cl2 molecules' translational energy enhance the near-IR laserinduced etching reaction Of the InP (100) surface.A chemical reaction mechanism isproposed that a rate determined step might be the controlling of factor the laser-induced thermal desorption of the adsorbed surface reaction products.