Abstract: Formaldehyde in aquatic products was determined by acetyle acetone spectrophotometry in the present research. The colorimetric parameters and the preprocessing of samples in the method were studied, and the feasibility of using acetyle acetone spectrophotometry as a method in rapid determination of formaldehyde in aquatic products was discussed as well. Results showed that the optimal soaking time was 10 min during ice incubation, then soaking solution pH value was adjusted to 6 with 100gL-1 KOH solution, and the optimal colorimetric time was 3 minutes at a wave length of 412 nm. The linear relation between absorbency and formaldehyde dosage was very good (R2=0.9998) while the formaldehyde content varied within a range of 0~2.5 gmL-1. The recovery of the present method was 89.50%~94.25%, while the recovery of the distillation method was only 64.17%~76.92%. Comparing with the latter method, the recovery of present method was much better. RSD (%) of the present method was 2.93%, and the minimum detectability of formaldehyde in samples was 0.9 mgkg-1.