Dandelion (Taraxacum mongolicum) was hydroponically cultured in a completely enclosed plant factory, in which fluorescence and LED emitting spectra of different bands were used as the sole light source for plant growth. Effects of spectral component on the growth of dandelion were studied and the contents of ten inorganic elements such as K, P, Ca, Mg, Na, Fe, Mn, Zn, Cu and B in dandelion were analyzed by ICP-AES technology. The results showed that: (1) Under the condition of similar photosynthetic active radiation (PAR), single R or combined spectrums of FLRB were beneficial for biomass accumulation, while single B was the contrary;(2) Macroelements content ratio in Taraxacum mongolicum grown under FL was K∶Ca∶P∶Mg∶Na=79.74∶32.39∶24.32∶10.55∶1.00, microelements content ratio was Fe∶Mn∶B∶Zn∶Cu=9.28∶9.71∶3.82∶2.08∶1.00;(3) Red light (peak at 660 nm) could promote the absorptions of Ca, Fe, Mn, Zn, while absorption of Cu was not closely related to spectral conditions;(4) The highest accumulation of Ca, Na, Mn and Zn were obtained in aerial parts of Taraxacum mongolicum plants grown under pure red spectrum R, while the accumulation of the rest six elements reached the highest level under the mixed spectrum FLRB.