Under the condition of weak acidity of pH 5.2, a sensitive vitamin B₂ electrochemical sensor based on molecularly imprinted nonconducting polymer of o-aminophenol by potentiostatic polymerization in the presence of template(vitamin B₂) on a glassy carbon electrode was prepared, and its performance was studied. The sensor exhibited good sensitivity and selectivity to VB₂. The detection limit went down to 2.3851nM, and a linear relationship between the current incremental and the concentration was found in the range of 10～120nM. And the sensor could use in detection of VB2 real sample for a long time and show good reproducibility. The average recovery rate to VB2 was 98.41%.