The use of nanoparticles (NPs) is recently increased due to their many applications in many different sectors. The majority of the methods used to manufacture of nanoparticles is mostly harmful to the environment and have high costs. The aim of the current work is to step forward in production silver NPs in a way with less cost and harm to environment using the green biosynthesis route. The Silver NPS colloidal suspension is produced based on the reaction of the metal precursor AgNO3 and a Cactus extract using Microwave instead of thermal heating. Optimization and modeling of NPs synthesis at lab scale is carried out throughout 10 experiments designed using software for experimental design and treating the responses statistically. The effect of concentration the metal precursor and power of microwave on the formation time of the NPs is investigated using Response Surface Methodology. The statistical results showed that the microwave power is more significant than the metal ions concentration, and the Ag NPs formation time decreased with increasing the microwave power and metal ions concentration. The optimum value for NPs formation time estimated is 10.27 minute. This formation time could be achieved using microwave power of 129.05 Watt and 1.8 ml of AgNO3 solution. The equilibrium adsorption data of methylene blue dye on the synthesized silver NPs were mathematically modeled by employing the pseudo-first-order kinetics equation and the photo-catalytic performance was inspected throughout the degradation of methylene blue under irradiation by sunlight. The dye was effectively nearly 99% degraded by the green synthesized silver nanoparticles after 72 hours of exposure to sunlight