Clorprenaline,a β2-adrenergic agonist,was first found in veterinary drugs for cold treatment in China in 2013.It is a potential new lean meat-boosting feed additive because it can promote animal muscular mass growth and decrease fat accumulation.A competitive colloidal gold-based lateral flow immunoassay system with a portable strip reader was successfully developed for rapid quantitative detection of clorprenaline residue in swine urine.The detection system was optimized so that the detection can be completed within 9 min with the limit of detection of 0.15 μg·l-1.The assay exhibited good linear range from 3.0 μg·l-1 to 20.0 μg·l-1 with reliable correlation of 0.9970 and with no obvious cross-reaction with five other β2-agonist compounds.Twenty spiked swine urine samples were tested by lateral flow immunoassay and LC–MS/MS to confirm the accuracy of the system.Results show good correlation between the two methods.This method is rapid,sensitive,specific,and convenient.It can be applied in the field for on-site detection of clorprenaline in urine samples.