To clarify the impacts of artificial light spectrum and illumination intensity on the photosynthetic indices of landscaping plants, spectral irradiation experiments were conducted on Photinia serrulata at three light intensities with five different light emitting diode(LED) light emitting cliode. Analysis of the relationship of artificial light spectrum，light intensity，the net photosynthetic rate and photosynthetic active radiation. Results showed that: At the same light intensity, photosynthetically active radiation of plant was the highest under sunlight, which was far higher than that under the LED light sources. Under LED lights, net photosynthetic rate of Photinia serrulata rose with enhancing light intensity. Under green LED light (530 nm), photosynthetically active radiation of plant increased with enhancing light intensity. However, net photosynthetic rate remained negative all along.