Abstract: In order to study the relationship between the development trajectory of emotion inferences and narrative comprehension, 100 children and 100 adults were selected to investigate how children and adults process negative emotions during reading and how they can affect themselves and the protagonist’s emotional state.The results show that: (1) Negative emotions promote the processing of target sentences in children and adults. (2) For adults, negative emotions promote the processing of spillover sentence. While for children, negative emotions inhibit the processing of spillover sentence, which indicates children need more time to deal with the protagonist’s emotional state and integrate them into a coherent psychological representation. (3) Children and adults have similar ratings for the valence and arousal of emotional state. They all think that the emotional state of the protagonist is more negative and stronger than their own emotional state. However, children rated their emotional state as relatively neutral, while adults’ evaluation of their emotional state is closer to the protagonist’s negative emotional state, which suggests that there may be differences in the emotional reasoning mechanisms between children and adults.