A three-dimensional analytical thermal model of the homojunction Burrus-type light-emitting diode is presented in this work. Boundary conditions of the thermal conduction equation are formulated on the basis of analog electrical model of the heat-spreading process within the diode structure. The heat-flux penetration into the high-resistivity region and its conduction through the dielectric film, the current-spreading between the upper contact and the active region as well as the temperature dependence of the thermal conductivity are taken into account. The Green functions method is used for solving the thermal conduction equation. Its solution enables us to analyze a relative influence of various construction parameters on temperature increases in the active region.