Selective area growth (SAG) is performed to fabricate monolithically integrated distributed feedback (DFB) laser array by adjusting the width of a SiO2 mask. A strain-compensated-barrier structure is adopted to reduce the accumulated strain and improve the quality of multi-quantum well materials. Varying the strip width of the SAG masks, the DFB laser array with an average channel spacing of 1.47 nm is demonstrated by a conventional holographic method with constant-pitch grating. The threshold current from 14 to 18 mA and over 35-dB side mode suppression ratio (SMSR) are obtained for all DFB lasers in the array.