The present invention provides a two solenoid valve relay with a two-phase fuel injection valve for a diesel engine, which is installed on a valve itself to enable injection at pressure greater than opening pressure, at which the fuel enters into a fuel valve, thereby improving fuel injection performance, and which is configured to enable adjustment of an injection timing at the opening pressure within the valve, wherein injection timings through a solenoid valve is provided for low load and high load, respectively, such that a distinct difference exists between the injection timings to open the nozzle hole of the nozzle in a differential manner at pressure higher than the pressure, at which the fuel enters to the fuel valve and internal spring opening pressure, thereby injecting fuel at high pressure even at low load to facilitate vaporization, and wherein, in case of a high speed operation or high load, low pressure/high pressure needle valves are opened at the same time to quickly inject fuel of a high volume through a plurality of nozzle holes, thereby improving combustion performance of an engine, and wherein a space between the needle valve and the nozzle hole which are closed after the injection is minimized because the nozzle hole is opened differentially and sequentially according to pressure, thereby avoiding waste of fuel and reducing harmful gas (smoke, Nox).