Photoinduced anisotropy in bacteriorhodopsin (BR) film arises from the selective bleaching of BR molecules to linearly polarized light. The kinetics of photoinduced anisotropy excited by single and two pumping beams are investigated theoretically and experimentally. Compared with a single pumping beam ( $650\mathrm{nm}$ ), which produces comparatively small photoinduced anisotropy, dual-wavelength linearly polarized pumping beams (650 and $405\mathrm{nm}$ ) can obviously change the photoinduced anisotropy. When the polarization orientation of the $405\mathrm{nm}$ pumping beam is perpendicular to that of the $650\mathrm{nm}$ pumping beam, the peak and steady values of the photoinduced anisotropy kinetic curves are remarkably enhanced. But when the two pumping beams have parallel polarization orientation, the peak and steady values are restrained. At a fixed intensity of the $650\mathrm{nm}$ pumping beam, there exists an optimal intensity for the $405\mathrm{nm}$ pumping beam to maximize the value of the photoinduced anisotropy. The photoinduced transmittance of the polarizer-BR-analyzer system is modulated by the polarization angle of the $405\mathrm{nm}$ pumping beam in an approximate-cosine form.