Objective To study the effect of channel bend number and length on foam stability of varicose vein foam sclerotherapy. Methods Three groups of experiments were set up: experimental group 1 with different channel turns (channel turn of subgroup A, B, C was 1, 2, 3, respectively), experimental group 2 ( control group) with different channel total lengths ( total length of subgroup A, B, C was 2, 6, 10, respectively), experimental group 3 with different channel length ratios (ratio of long and short sides for subgroup A, B, C was 1 ∶1, 5 ∶1, 9 ∶1, respectively). A 5 mL syringe was used, the liquid-gas ratio was 1 ∶4, and the Tessari method of CO2 and air was used to prepare foam experiments at room temperature. The whole process of experiments on each group was photographed, and the experiment was repeated 5 times. Data such as water separation time, half-life, and water separation rate curve were obtained by video playback. Results In experimental group 2, the water removal rate of CO2 foam was 40% and 80% , and there were significant differences between subgroup A, subgroup B and subgroup C. In air foam, there is a significant difference between subgroup B and subgroup A with a water separation rate of 20% and 50% ; for all water separation rates, subgroup C and subgroup A had a significant difference. The total length of the channel had a more significant impact on the CO2 foam. The longer the total length of the channel, the more stable the foam would be. Compared with control group, the CO2 foam in experimental group 1 had a significantly higher water separation rate curve than that in the control group, while the air foam overlapped and crossed, and the difference was not obvious. Compared with the control group, the curve of the CO2 foam in experimental group 3 was significantly higher than that in control group, while the air foam was only significantly higher than that in control group when the water separation reached 100% . The influence of the channel length ratio was more obvious in CO2 foam. The half-life had a greater impact in CO2 foam. Conclusions The number of channel turns used to prepare the foam enhances stability of the foam. The increase in total length of the channel has a positive effect on stability of the foam, and the ratio of the channel length has a greater influence on stability of the foam. The results have certain significance for clinical preparation of foams and the stability research of other foams.