The present invention provides a LTPS TFT substrate, which includes a black matrix arranged on a first buffer layer of the LTPS TFT substrate to have an area where a TFT device is located is shielded by the black matrix thereby preventing the TFT device from being influenced by light irradiation, maintaining stability of the TFT device; and also saving the manufacturing process of a shielding metal layer, reducing one photo-mask, and lowering down manufacturing cost so as to allow the black matrix, in achieving the functionality of its own (shielding leaking light of the pixel), to also take the place of a shielding metal layer that is commonly adopted in the prior art to shield light for the TFT device and thus providing duality of functionality.