This article is based on the theory of speech acts and J. Searle's classification of speech acts to investigate and categorize speech acts of children in communication with adults according to three age types: children aged 4-6 with adults, children aged 6-11 with adults, and children aged 11-15 with adults. The research results show that in their communication with adults, children employ all five categories of speech acts, consisting of 64 speech acts and 4,275 times of speech acts. There are variations in the number of speech acts within each types, influenced by communication factors such as the communication context, communication topic, and communication content. This reflects the children's natural, innocent, yet resolute and responsible language abilities and characteristics in their interactions with adults.