The sap flow of cultivar Oriental-Trumpet hybrids Lilium “Robinna” studied with packaged sap flow system,basis on monitoring environment factors.The results of statistical analysis indicated that during the periods of growth of Lilium (158 days),the total capacity of sap flow was 7 289.30 g,46.13 g per day.Among the periods of stooling stage,squaring stage,flowering stage,fruiting stage and post fruiting stage,sap flows were 1 862.00 g,3 197.80 g,710.50 g,1 438.30 g,116.70 g and averages were 62.97 g,72.68 g,54.65 g,30.60 g,4.67 g,respectively.Sap flow rate was obviously different in the different periods of growth of Lilium.The radiation and temperature were major factors affecting sap flow.Sap flow rate was positively correlated with radiation and temperature,negatively correlated with relatively humidity.Sap flow and Sap flow rate in rainy days and cloudy are lower than that in sunny days.This research establish the theoretical foundation of water metabolism model and water-saving cultivation of Lilium.It has important significance to adopt appropriate water-saving cultivation model of Lilium.