The cold-rolled production line of double-line continuous electrolytic pickling is quite common in the manufacture of all kinds of small-diameter cold-rolled thread steel. This paper studies the main technology parameters, the main device with the structure characteristics and the principle of the cold-rolled production line of double-line continuous electrolytic pickling, and then analyzes on the experiments and on the technological economics for the small-diameter cold-rolled thread steel. The results show that its production line is convenient in operation, accurate in processing, efficient and adaptable in production. The small-diameter cold-rolled thread steel produced by this production line has high strength, large plasticity and good yield performance and bending characteristics. It can greatly improve the performance of reinforced concrete structure and prestress reinforced concrete structure, increases the quality of components, and saves steel about 15%. So it is a high efficiency, energy-saving steel. Small-diameter cold-rolled thread steel is widely used in the construction industry with very significant economic and social benefits, it plays an important role to accelerate the economic construction of China.