Top: photo-z results from data with only one noise realization. Each panel shows the z_output vs. z_input for CSST-only (upper left), Euclid+CSST (upper right), Euclid+LSST-like setup (lower left) and Euclid+DES-like setup (lower right), respectively. The red solid and dashed lines indicate z_photo = z_input, and |δz|/(1 + z_input) = 0.15, respectively. Bottom: photo-z results from 20 sets of data with different noise realizations.