The impact of spectral scan intervals on the chromaticity measurement and the quality analysis of energy-saving lamps has been researched. An integrating sphere and spectrometer system with the spectral scan interval of 1nm and 5nm was employed to measure the spectrum, color temperatures, rendering indexes and chromaticity coordinates of light sources relatively. Results show that the spectrum differs significantly at the peak near 610nm with the measuring condition of 1nm and 5nm scan intervals, all the color temperatures measured by 1nm spectral scan interval are larger than that of 5nm, while all the rendering indexes are smaller. The ΔTc max is 41K and ΔRa max is 0.5. An optimal method of measuring the color of light sources is proposed based on this research.