Abstract: Solution culture was carried out to study the effect of nitrogen sources and potassium supply levels on growth and chlorophyll content of hybrid rice, its parent lines, and conventional rice The results showed that the chlorophyll content, growth index, and nutrition content of different varieties were closely related to potassium supply levels and N sources Comparing to high K supply, low K supply for each variety resulted in lower plant height, shorter root length, less dry weight, and lower chlorophyll content Hybrid rice and its parent lines had greater response to N sources than conventional rice at the high potassium level Hybrid rice showed better heterosis when supplied with NO3--N under high K supply level than with either NH4+/ NO3--or NH4+-N