Method for detecting wrapping oil

The invention discloses a method for detecting wrapping oil. The method comprises 1, measuring L0 and b0 values of DAP of unwrapping wrapping oil through a colorimeter, 2, wrapping the DAP treated through the step 1 with the wrapping oil, 3, measuring the L value and b value of the DAP treated through the step 2 with the colorimeter, 4, calculating the values of delta L=L-L0 and delta b=b-b0, and5, determining whether the wrapping oil is qualified, wherein when the delta L is greater than -2.0 and delta b is greater than -2.0, the wrapping oil is qualified and when the delta L is less than orequal to -2.0 and delta b is less than or equal to -2.0, the wrapping oil is unqualified. The method can detect the appearance quality of wrapping oil and measure whether different batches of wrapping oil are qualified. The DAP wrapped by the qualified wrapping oil has the bright yellow surface and beautiful appearance and satisfies the DAP appearance requirements.