Abstract: Formaldehyde content in waterishlogged food products (water risen sea cucumber) was measured by using spectrophotometer, and the various factors affecting measurement were analyzed and assessed. Then the mathematical model of uncertainty was established to systematically calculate the uncertainty of each components and the uncertainty of the influencing factors. The results showed that the main factors affecting formaldehyde content measurement in waterishlogged food products were the repetitive operating process in test, the accuracy of the standard operating fluid and the accuracy of the concentration of distillate.