采用正向电压法测量不同衬底温度、不同电流驱动时，双荧光粉转换型白色LED的结温，同时采用光谱仪测量归一化光谱分布.选择芯片的蓝色光谱，计算其质心波长和半高全宽，得到质心波长、半高全宽、驱动电流和结温四者之间的变化规律图.然后根据实际点灯状态下芯片的光谱特征参数，结合规律图计算得到实际结温.研究表明：对于环境温度变化引起的结温变化，（B+Y+R）/B法与本文方法准确度相当，测量误差均为2℃左右，无统计性差异.对于电流变化引起的结温变化，本文方法误差仍然约为2℃，而（B+Y+R）/B法误差与电流正相关，变化率为0.048℃/mA.同时在点灯6周内，本文方法误差仅4℃.因此，本文方法不仅适合因环境温度和驱动电流变化引起的结温变化，且无需重新校准，能准确测量长时间点灯LED结温，具有明显的技术优势.

The junction temperatures of LED with different ambient temperatures and drive currents were measured with the Forward Voltage method, at the same time, the normalized spectral distributions were measured with spectrometer.The specific spectral distribution of blue chip was selected to calculate its centroid wavelength and full width at half maximum, and then the relationships among these two parameters, drive current and junction temperature were obtained. At last, the junction temperature of the LED at the lighting condition was obtained with the relationships and the measured spectral feature parameters of the chip. It was found that for the junction temperature changed with ambient temperature, the measured error of this method and (B+Y+R)/B method were both about 2 ℃, and no statistical significance. For the junction temperature changed with drive current, the measured error of this method was always 2 ℃. However, the error of the (B+Y+R)/B method was positively correlated with the current, with the change rate of 0.048 ℃/mA. Therefore, the established method was suitable for determining the junction temperature with the change of not only ambient temperature, but drive current, and it was also accurate when LED lighting for a long time without re-calibration, which showed significant technical advantages.