In order to investigate the capillary discharge plasma characteristics and its interaction with propellants

we reviewed the models of the eletro-thermal chemical（ETC） launch system. Meanwhile

we divided this system model into three sub-models

namely

the capillary discharge model

the plasma jet model

and the plasma propellant interaction（PPI） model. In these sub-models

the basic principles of the ablation model

capillary discharge plasma magneto-hydrodynamic（MHD） model

plasma-jet model

heat transfer model and kinetic chemical model of the PPI were introduced. The development history of these models was discussed

and the advantages and limitations for these models were compared. The results show that the modified kinetic ablation model considering the effect of the plasma pressure and temperature matches the transient ablation process in the capillary discharge well. The distribution of plasma temperature and density at the capillary exit is uneven

so the two-dimensional capillary model is necessary. In the plasma-air and PPI model

the chemical reactions between plasma and air or propellant cannot be neglected. In the future work

the combination of the MHD model and kinetic chemical model should be explored to predict the ignition characteristics of different propellants more accurately.