With 10 rice cultivars (lines) as materials, the changes in activities of adenosine diphosphoglucose pyrophosphorylase(ADPGPase), starch synthase (SSase) and starch branching enzyme (Q-enzyme) in the grains during grain filling, and theirrelationships with the filling rate, gel consistency (GC), alkali spreading value (ASV) and amylose content (AC) werestudied. The results showed that changes in activities of ADPGPase, SSase and Q-enzyme exhibited a single peak duringgrain filling, and the time of the activity peaks for the former two enzymes was earlier than that of the maximum grain-fillingrate (Tmax), and the time reaching the peak for Q-enzyme was synchronous with Tmax. The activities at early grain fillingstage, and the mean and maximum activities of each enzyme during grain filling period were positively and significantly orvery significantly correlated with the mean and maximum grain filling rate and starch content (mg grain-1) in the grains.Activities of ADPGPase at all grain filling stages and those of Q-enzyme at the early and mid filling stages were notsignificantly correlated the cooking quality (GC, ASV and AC). SSase activities at the early filling stage were significantlyand negatively correlated with GC and ASV, and positively correlated with AC. Activities of SSase at mid and late grainfilling stages and Q-enzyme at the late filling stage were significantly and positively correlated with GC and ASV, andnegatively correlated with AC. Spraying zeatin or abscisic acid at early grain filling stage could obviously regulate theactivities of ADPGPase, SSase and Q-enzyme in the grains. With 10 rice cultivars (lines) as materials, the changes in activities of adenosine diphosphoglucose pyrophosphorylase (ADPGPase), starch synthase (SSase) and starch branching enzyme (Q-enzyme) in the grains during grain filling, and their relationship with the filling rate, gel results (GC), alkali spreading value (ASV) and amylose content (AC) were stutied. The results showed that changes in activities of ADPGPase, SSase and Q-enzyme showed a single peak during grain filling, and the time of the activity peaks for the former two enzymes was earlier than that of the maximum grain-filling rate (Tmax), and the time reaches the peak for Q-enzyme was synchronous with Tmax. The activities at early grain filling rate, and the mean and maximum activities of each enzyme during grain filling period were positively and significantly orvery highly correlated with the mean and maximum grain filling rate and starch content (mg grain-1) in the grains. Activations of ADPGPase at all grain filling stages and those of Q-enzyme at the early and mid filling stages were not statistically associated with the cooking quality (GC, ASV and AC). SSase activities at the early filling stage were significantly and negatively correlated with GC and ASV, and positively correlated with AC Activities of SSase at mid and late grain filling stages and Q-enzymes at the late filling stage were significantly and positively correlated with GC and ASV, and negatively correlated with AC. Spraying zeatin or abscisic acid at early grain filling stage could obviously regulate the activities of ADPGPase , SSase and Q-enzyme in the grains.