High power chip-on-board light emitting diode (HPCOBLED) is a promising solid state light technology for a variety of lighting applications. In this paper, the authors study temperature effect on luminous flux of HPCOBLED using VMI-PR-001 system of Vietnam Metrology Institute. The results show that when the case temperature (Tc) increases. luminous flux decreases. In particular, when HPCOBLED is of high power, the decrease of luminous flux is larger. An explanation for this result is consumed power on the LED. the authors proposed HPCOBLED model'modifiedfrom Hodapp's model using temperature gradient between p-n junction of device and heat radiator for description of the temperature effect on luminous flux of HPCOBLED. The calculation results for the modified HPCOBLED model match with those experimental values measured by the luminous flux measurement system (VMI-PR-001, Vietnam).