The invention discloses an in-situ test system for magnetoelectric stress coupling of a nitride light emitting diode, comprising: a nitride light emitting diode, an external current source, an XRD test component and a magnetic field generating device, and is characterized in that the side wall of the nitride light emitting diode is formed Magnetic material, pass current through the P-type electrode and N-type electrode of the nitride light-emitting diode, place it on the sample stage of the XRD test assembly, generate a magnetic field around the nitride light-emitting diode through a magnetic field generating device, and make the nitride light-emitting diode Light-emitting diodes produce magnetic field-electric field-stress coupling effects, and use XRD single crystal diffraction to test the lattice constant of light-emitting diodes in the process of magnetic field and electric field changes in situ, and then control the magnitude of the magnetic field and electric field in situ, and adjust the stress change of nitrides , so that the light-emitting diode can obtain the highest luminous efficiency.