In recent years, applied researches has an environmental approach and healthy and safty is very important. Petroleum pollutant (including crude oil and its derivatives) and negative effects of that on environment is one of the problems. With this respect, current research was done to evaluate the effect of light and aeration on the potential of cyanobacterium Schizothrix vaginata in biodegradation of oil pollutant. In this way, after gaining axenic culture, experimented cyanobacterium was treated with naphthalene 0.05% and hexadecane 1% under different aeration and light (0, 2000 and 5000 lux) culture condition. When the alga was in logarithmic phase of growth, OD, DW, chlorophyll, phycobiliprotein and biodegradation ability was eavaluated. OD, Chl and phycobiliprotein were calculated spectrophotometrically and DW with gravimetric methods. Naphtalene and hexadecane was measured with GC. Results of the effect of experimented factors on indicated that light without aeration increased the biodegradation of hexadecane and naphthalene 4 and 8% respectively. But light plus aeration increased this ability 22 and 28%. Growth and pigmentation in both treatments increased with light and decreased with aeration. According to the result light and aeriation have positive effect on biodegradation of naphthalene and hexadecane.