Metasurfaces have exhibited powerful capabilities in the modulation of electromagnetic waves. Here, we demonstrate the polarization-selective full-space complex amplitude modulations of incident electromagnetic waves using all-dielectric metasurfaces. This is done via ingeniously designed subwavelength-scale super-pixels. As a proof of concept, we design two metasurfaces working in transmission and reflection spaces: one generates two independent vortex beams and the other generates two pairs of foci of arbitrary intensity ratios. The proposed full-space complex amplitude modulation provides more choices for the manipulation of electromagnetic waves.