With the development of beam combining and the improvement of unit chip power, diode lasers have shown their own advantages in the field of laser processing. Aiming at the requirement of thermal curing of glass fiber reinforcement bars in the field of laser processing, the single tube laser with the power of 18 W is used as the unit module. The laser heating light source with the output power of greater than 2 kW, the wavelength of 915 nm, and the spot size of 700 mm×10 mm is obtained through the combination of spatial multiplexing, polarization multiplexing, and beam shaping technology, which meets the requirement of high power and long spot laser heating in industry.