Abstract: The effects of light intensity on oxygen production and consumption rates of Gracilaria lichevoides were studied by “light-dark bottle” oxygen method in indoor and outdoor experiments. The results indicate that under 20 000 lx the rate of oxygen production by G. lichevoides and the light intensity showed linear relationship by correlated equation of y=0.000 144 3x-0.122 1 (R²=0.993 8). The oxygen consumption rate of G. lichevoides was 0.121±0.010 mg/(g·h), the light compensation point was 825 lx, the saturation point was between 20 000 and 22 000 lx and the oxygen production rate at light saturation point was 2.723±0.329 mg/(g·h). The oxygen production rate was basically unchanged when light intensity was above light saturation point, but it decreased slightly and showed a slight photo-inhibition above 45 000 lx. The light intensity, measured with the changes of water depth, showed that it was 14 000-15 000 lx when the water depth was less than the Secchi depth, and under this light intensity, the growth rate of G. lichevoides reached the highest. It was found that exorbitant breeding density could occur aquatic hypoxia early in the morning by measuring diurnal variation of dissolved oxygen concentration in different cultivation mode. According to the photosynthesis characteristics of G. lichevoides, methods by adjusting the depth of the water for G. lichevoides cultivation or bioremediation, and controlling breeding density for ecological aquaculture were proposed to maintain high economic and ecological benefits for the request of different conditions.