A process for electrodeposition of silicon belongs to the electroanalysis and electrophoresis technology field and used forone-step electrodeposition of silicon from SiO2 by using molten salt as medium and adoping direct current. Said process is characterized as follows: using a 3-constituent element composed of NaCl, KCl and NaF as medium, wherein the mol ratio thereof is 1:1:0.5-1:1:4.5, and adding powdery SiO2 which mass is 10% of the fused-salt medium mass therein; after pre-electrolysis impurities removing, electrodepositing pure silicon with electrodeposition temperature of 800 -950 DEG C, electrodeposit time of 0.5 -3 hours and ampere density of 500-1000 A/m2.The present invention is characterized as follows: 1, the constituent elements forming molten salt are usual and cheap pharma-ceutical products which are easy to obtain, then the cost is low and the consumption is small; 2, the manufacturing technique is simple and the process is easy to control. Said process in accordance with the present invention possesses excellent applications foreground in semi-conductor devices fabricating.