Abstract: This paper introduces theoretical formulation optimization and ignition and combustion experiments of liquid propellant. A spacer nuid formulation of easy compounding, low viscosity, high stability and no formation pollution are selectad through analyzing different spacer fluid formulations and their experiment results. Well and layer selection criteria of liquid propellant high energy gas fracturing (HEGF) are included in this paper. Several key problems existed in field operation of liquid propellant are solved and field experiment results are given also. At last, this paper presents some views on the future trend of liquid propellant HEGF.