The present invention provides a manufacture method of a LTPS array substrate. By utilizing one halftone mask, the N type heavy doping, the channel doping of the first polysilicon layer of the NMOS region and the P type heavy doping of the second polysilicon layer of the PMOS region, the three processes which previously require three masks are integrated into one mask process, and two exposure processes are eliminated, which significantly raises the exposure capacity, and meanwhile saves the manufacture cost of two masks to effectively reduce the manufacture cost of the LTPS array substrate, and the manufactured LTPS array substrate possesses great electrical property.