The design method for implosion capsules with low convergence ratio driven by radiation was dweloped. These kinds of the capsules used for the experiment on Shenguang II (SG-II) and Shenguang III prototype (SG-III-P) laser facilities were simulated using Multi-1d code. The implosion targets were designed, and the variations of convergence ratio, neutron yield and area density vs fuel pressure were obtained from the simulation. Two kinds of implosion targets with low convergence ratio on SG-II which were filled with DD and DT fuels respectively and a kind of the target on SG-III-P filled with DD were designed. The neutron yield calculated by Multi-1d with low convergence ratio agreed with the experimental data on Shenguang II laser facility. It showed that Multi-1d is reliable for use with these experiments.