In order to systematically study residues and degradation rules of forchlorfenuron in facilities muskmelon, and promote safety to production, a residue analytical method has been developed for the determination of forchlorfenuron in facilities muskmelon by screening sample preparation methods and equipment chromatographic conditions. At the same time, the degradation and residue of forchlorfenuron in facilities muskmelon were studied by means of high performance liquid chromatography (HPLC). The results showed that the recoveries were 92.6%-110%, and the relative standard deviations of the method were 0.00%-7.32%. The minimum detectable concentration of forehlorfenuron was 0.006 mg/kg and the minimum detectable amount of forehlorfenuron was 1.2×10-10 g, and the linear relationship was obtained in this method (r=0.9997). The degradation rate of forchlorfenuron in facilities muskmelon was fast with half-life of 1.52 days. No forchlorfenuron residue was detected in facilities muskmelon with a harvest withholding period of 52 days after the treatments (＜0.006 mg/kg) and lower than 0.01 mg/kg (MRL value). So it was safe to dip application of 20-30 a.i. mg/kg water on female flowers opening in the same day or 2-3 days before flowering.