Abstract: To investigate the residue elimination patterns of diazepam in crucian carp (Carassius auratus), one of the major freshwater fish species consumed in China, we used a combined approach involving laboratory simulation, pilot-scale pond study, and validation with actual positive samples to systematically explore them. In indoor simulations, crucian carp were exposed to a 12 μg·L⁻¹ diazepam bath for 2 h and then transferred to clean water. Diazepam concentrations in muscle tissue were below the limit of detection (0.5 μg·kg⁻¹) within 2 d. However, the concentration remained at 1.70 μg·kg⁻¹ in crucian carp which were transferred to the water containing 200 ng·L⁻¹ diazepam on the 90^th day. Nordiazepam was the primary metabolite of diazepam in the muscle of crucian carp. The pilot-scale pond study demonstrated that almost no diazepam residues were detected in crucian carp after 4 h when exposed to 1 μg·L⁻¹ diazepam for 2 h and then transferred to a pond with a diazepam concentration below 5.0 ng·L⁻¹. However, on the 60^th day after being transferred to a pond with a diazepam concentration of 65.64 ng·L⁻¹, the concentration exceeded the detection limit. The actual positive sample verification results showed that crucian carp with initial diazepam concentration of 2.80 μg·kg⁻¹ required one week of depuration in clean water to be detected as qualified. These results indicate that the diazepam concentration in aquaculture water is the key factor influencing the elimination rate of diazepam in cultured carp muscle, and depuration in clean water is a simple and effective method for eliminating diazepam residues from aquatic products.