The improper knowledge of mothers is the most causes of the onset of malnutrition in young children. Growth chart is an essential tool in growth monitoring program for malnutrition prevention among children. This study is to investigate the impact of the modified growth chart that is called "Bubble Score Growth Chart" on mothers' knowledge and child calorie intake. Mothers in intervention group used bubble score growth chart while mothers in control group used the normal growth chart. Sixteen written questions were designed and tested to measure mothers' knowledge. Results : Before intervention, there was no significant difference of mothers' knowledge, comprehension and application(p>0.05) and child calorie intake (p>0.05) between intervention and control group. After intervention, there was significantly different of high knowledge (86% vs 52%); high comprehension (86% vs 54%) and high application (78% vs 46%, p<0.01) and high calorie intake (74% vs 46%, p<0.01) respectively for intervention and control groups. Modified growth chart effectively improved mothers' knowledge and child calorie intake.