Microbump structures were formed on the sample surface after micromachining the Cr films by polarized femtosecond double pulses with nanojoule energy and high repetition rate. Although the widths of the microbumps have no obvious variation among the 0～400 ps double pulses delay, the heights of them exhibit an obvious drop among the 1～10 ps double pulses delay and have no obvious variation beyond this delay. It is helpful to understand the electron–phonon coupling process in metal film during femtosecond laser micromaching. Furthermore, better micromachining quality was acquired with double pulses method for both linearly and circularly polarized light according to the scanning electronic microscope (SEM) images. Contrast to nearly circular microbumps fabricated by circularly polarized light, the microbumps fabricated by linearly polarized light is narrow and stretched in the direction of polarization of the incident beam. Namely, the micromachining feature is related to the polarized state of the incident beam with low pulse energy and high repetition rate.