The ion yield curves for C-70-2n(z+) (n = 1-8, z = 2 and 3) produced by photoionization of C-70 were measured in the photon energy (hv) range of 25 - 150 eV. The appearance hv values were higher by ca. 34 eV than the thermochemical thresholds for dissociative ionization of C-70 leading to C-70-2n(z+). Evaluation was made on the upper limits of the internal energies of the primary C-70(z+) above which C-70-2n+2(z+), fragments cannot escape from further dissociating into C-70-2n(z+)+C-2. These critical internal energies agreed well with appearance internal energies of C-70(z+) theoretically obtained corresponding to the threshold for the formation of C-70-2n(z+). The photofragmentation of the parent C-70(z+) ions is considered to be governed by the mechanism of internal conversion of their electronically excited states, statistical redistribution of the excess energy among a number of vibrational modes, and sequential ejection of the C-2 units.