Based on the beam propagation dynamic equation with the photovoltaic effect of the uniform background illumination, it is theoretically demonstrated that gray photovoltaic spatial solitons can exist in photovoltaic media with positive refractive index perturbation. When the beam is gray, the transverse phase profile varies in the fashion of (s)=vη-∫η0y-2()d, where v is the transverse velocity, η is a dimensionless coordinate, and y(η) is a normalized optical field amplitude. The impact of the grayness parameter m, the normalized intensity at infinity, the ratio (R) of effective Glass constants of the background beam to that of the signal beam on the FWHM and transverse velocity of gray solitons are discussed. The analysis of stability properties of these solitons is also given. When the grayness m=0, these gray solitons degenerate to photovoltaic dark solitons automatically.