ObjectiveTo investigate whether ultrasonic coupling agent (UCA) can produce shielding or antagonistic effect on iodine disinfectant for preoperative skin disinfection. MethodsShielding or antagonistic effect of UCA on iodine disinfectant were detected by laboratory carrier immersion killing test and onthespot skin disinfection test. ResultsAntagonistic effect: after the mixing of iodophor with UCA, the average killing rate of iodophor containing available iodine 2 500mg/L and 625 mg/L to Staphylococcus aureus decreased from 100.00% to 99.67%-99.78% and 96.85%-98.25%, respectively; the average killing rate to Escherichia coli decreased from 100.00% to 99.71%-99.82% and 95.93%-98.56%, respectively. Shielding effect: after smearing with UCA, the average killing rate of iodophor and iodine tincture +alcohol to Escherichia coli decreased from 100.00% to 30.76% and 100.00% to 94.48%, respectively; the average killing rate to Staphylococcus aureus decreased from 99.99% to 55.55% and 100.00% to 98.22%, respectively. Onthespot skin disinfection test: the killing rate of iodophor and iodine tincture +alcohol to natural bacteria on skin surface were both 99.99%, after skin  was smeared with UCA, the killing rate decreased to 92.62% and 93.57%, respectively. ConclusionUCA remained on the operative field has shielding and antagonistic effect on iodine disinfectant