Abstract: In order to decrease the temperature gradient between sample and substrate,reduce and suppress the thermal stress,improve the quality of sample forming,a substrate preheating system for laser metal deposition shaping(LMDS) is developed.It consists of substrates preheater,intelligent proportion-integral-derivation controller and computer serial collecting and feedback control components.Using the self-developed LMDS system and substrate preheating system,the actual experiments are conducted.Experimental results show that substrate preheating can significantly improve the quality of the sample and reduce the thermal stress during shaping process.