The important indiscriminate use of pesticides pollution of environment and leads a significant threat to beneficial microorganisms. The aims of this research is to perform the degradation of the pesticide by the cyanobacterial strains (Anabaena oryzae and Nostoc muscorum). So that the cyanobacteria are able to decrease insecticide contamination of rice fields by biodegradation of chlorpyrifos via measure nitrogen fixation rate, dry weight accumulation, total count of cyanobacteria, absorbance measurements by spectrophotometer and addition of gas chromatography–mass spectrometry (GC-MS) used to introduce the residuals components. The results refer to degrade all components of chlorpyrifos by cyanobacterial strains reach to 2.75 from 48 % after 12 days from incubation time. The mixture of Nostoc sp. and Anabaena sp. had increased in dry weight accumulation and raised the nitrogen fixation in environment. In addition to increasing in growth, yield and yield contributions for rice plant after inoculation with cyanobacterial strains particulars in mixture treatment compared to non-application by cyanobacteria.