Carbon nanotubes(CNTs) with uniform wall thickness were synthesized by a solid-liquid reaction route. Calcium carbide block and carbon tetrachloride as double carbon sources were enclosed in a 100ml stainless steel autoclave at 400°C for 8 hours. The fabricated products were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), and Transmission electron microscope (TEM). The research results indicate that the synthesized CNTs have lengths on the order of 10μm and external diameters in the range of 120-200nm. The nanotubes are typically the uniform inner diameters of 70nm and grow in the same direction. The growth mechanism is simply discussed.