Objective　To investigate the enhancement of color Doppler signals in lower limb arteries by intravenous ultrasound contrast agent.Methods　Nineteen cases examined were divided into two groups: Group I consisted of 13 normal cases; group II 6 cases with lower limb artery diseases. The contrast agents were administrated through forearm veins.Results　The color Doppler signals and flow width were all increased in normal lower limb arteries after the contrast agent was injected. No color Doppler signals were showed in 4 closed femoral arteries (FA) and popliteal arteries(PA) after enhancement of contrast agent, but the color flow were seen in 3 anterior tibial arteries (ATA) and 1 posterior tibial artery (PTA), which came from lateral vessels in the near end of ATA and PTA. In another 2 cases, a few color Doppler signals were showed in ATA and PTA before contrast admitted, but the color Doppler signals were increased and local color defect were presented after contrast admitted, in which the stenosis of arteries were confirmed by angiography.Conclusions　Intravenous ultrasound contrast agent could give rise color Doppler signals in lower limb arteries, and help to make lower limb artery disease diagnosis to a more accurate extent.