Abstarct: In this thesis, several methods for the synthesis of mextal nanoparticles with capability of control of process and their synthesis rate, has been investigated. Two general methods of chemical and mechanical milling were used for the synthesis of mextal nanoparticles such as copper, zinc, iron, magnesium and manganese. In chemical method which done with reduction of copper sulfate by glucose as reducing agent and with various mole ratios, cloidal mextal nanoparticles were synthesized. UV-Visible spectrometry of samples was taken several minutes after reaction which indicates successful synthesis of copper nanoparticles. The best result took place when mole ratio of glucose to copper sulfate was 1000 to 1 . Most important advantages of this synthesis method is possibility of synthesis of nanoparticles in large scales by increase of reagents but keeping of their ratio fixed. Nanoparticles synthesized by this method are unstable and agglomerate very soon after synthesis and form larger particles. To overcome this problem, effect of various atmospheres on stability of nanoparticles was investigated. Results showed that sample which was held in a dark place to prevent radiation of resonance wavelangthes is much stable than others. In the mechanical alloying method, a planetary ball mill was used for the synthesis of nanoparticles. Effect of various factors such as milling speed, milling time, weight of balls and powder in bowl, atmosphere inside the bowl, process control agent, material of bowl, size and size distribution of balls etc was investigated. Effect of these factors on the final result, are as below: - Although zinc nanoparticles were synthesized at milling speed of 180/560 rpm in a mextal grinding bowl, but by increase of milling speed and change of bowl material to teflone, nanosheetes and complicated two dimentional nanostructures was formed. - Increase of millimg time of zinc powder from 4.5 hours to 8 hours, lead to larger nanoparticles which maybe is due to cold welding between primarily synthesized nanoparticles. - Increase of weight of balls and so of powder, has an undesirable effect on the synthesis of nanostructures which is due to prevention of high energy collisions - Use of Argon and vaccum atmospheres inside the bowl, prevented from formation of oxide phases at the synthesis of copper, zinc, iron, magnesium and manganese nanoparticles - Effect of process control agent as a foctor for the prevention of cold welding by keeping other factors fixed, was investigated in the synthesis of copper, zinc and magnesium nanoparticles. Results indicated that in case of copper, size of nanoparticles become smaller.