A dual solenoid-relayed two-phase fuel injection valve for injecting fuel into a cylinder for a diesel engine, the fuel injection valve comprising: a distinguishing means configured to distinguish a pressure of fuel entering into a fuel valve into two phases of a low load and a high load, wherein the low load requires lower engine power and the high load requires higher engine power, and wherein the distinguishing means is composed of a low pressure solenoid valve adopted to operate when a low load is applied to open only a low pressure needle valve, and a high pressure solenoid valve adopted to operate with the low pressure solenoid valve when the high load is applied to simultaneously open the low pressure nozzle valve as well as a high pressure nozzle hole; a nozzle including a low pressure nozzle hole configured to be opened at the low load and a high pressure nozzle hole configured to be opened at the high load; a low pressure injection means configured to inject the fuel by opening only the low pressure nozzle hole in case of the low load to inject the fuel, the low pressure injection means comprising: a low pressure needle spring connected with the low pressure solenoid valve, which operates at the low load and a low pressure, through a fuel passage; a low pressure booster spindle connected with the low pressure needle spring; a low pressure needle valve connected with the low pressure booster spindle; a low pressure shuttle valve (150, 151) configured to discharge the fuel at a low pressure; and a high pressure injection means configured to inject the fuel by simultaneously opening the low pressure nozzle hole as well as the high pressure nozzle hole in case of the high load to inject the fuel, characterized in that the low pressure injection means enables fuel pressure to be maintained from the low pressure needle valve to a high pressure needle valve through a fuel oil inlet, wherein, at the same time, fuel through the lower pressure shuttle valve (150, 151) and a high pressure shuttle valve affects the low pressure booster spindle and a high pressure booster spindle to operate at atmospheric pressure such that the low pressure needle valve and the high pressure needle valve rest motionless at pressures higher than pressure of the fuel entering from an injection hole, and when required pressure of the low load is reached, the low pressure solenoid is operated such that relative pressure applied to the low pressure booster spindle is discharged to a drainage through a lifting bush valve to interwork with the low pressure needle valve, thereby opening the low pressure nozzle hole to inject the fuel. a distinguishing means configured to distinguish a pressure of fuel entering into a fuel valve into two phases of a low load and a high load, wherein the low load requires lower engine power and the high load requires higher engine power, and wherein the distinguishing means is composed of a low pressure solenoid valve adopted to operate when a low load is applied to open only a low pressure needle valve, and a high pressure solenoid valve adopted to operate with the low pressure solenoid valve when the high load is applied to simultaneously open the low pressure nozzle valve as well as a high pressure nozzle hole; a nozzle including a low pressure nozzle hole configured to be opened at the low load and a high pressure nozzle hole configured to be opened at the high load; a low pressure injection means configured to inject the fuel by opening only the low pressure nozzle hole in case of the low load to inject the fuel, the low pressure injection means comprising: a low pressure needle spring connected with the low pressure solenoid valve, which operates at the low load and a low pressure, through a fuel passage; a low pressure booster spindle connected with the low pressure needle spring; a low pressure needle valve connected with the low pressure booster spindle; a low pressure shuttle valve (150, 151) configured to discharge the fuel at a low pressure; and a low pressure needle spring connected with the low pressure solenoid valve, which operates at the low load and a low pressure, through a fuel passage; a low pressure booster spindle connected with the low pressure needle spring; a low pressure needle valve connected with the low pressure booster spindle; a low pressure shuttle valve (150, 151) configured to discharge the fuel at a low pressure; and a high pressure injection means configured to inject the fuel by simultaneously opening the low pressure nozzle hole as well as the high pressure nozzle hole in case of the high load to inject the fuel, characterized in that the low pressure injection means enables fuel pressure to be maintained from the low pressure needle valve to a high pressure needle valve through a fuel oil inlet, wherein, at the same time, fuel through the lower pressure shuttle valve (150, 151) and a high pressure shuttle valve affects the low pressure booster spindle and a high pressure booster spindle to operate at atmospheric pressure such that the low pressure needle valve and the high pressure needle valve rest motionless at pressures higher than pressure of the fuel entering from an injection hole, and when required pressure of the low load is reached, the low pressure solenoid is operated such that relative pressure applied to the low pressure booster spindle is discharged to a drainage through a lifting bush valve to interwork with the low pressure needle valve, thereby opening the low pressure nozzle hole to inject the fuel.