Conflict control refers to an individual's goal-directed cognitive control and self-regulation of behavior. The neurodevelopment related to conflict control is crucial for the development of cognitive and emotional abilities in children. In the current study, preadolescent children and adults completed the Simon and Stroop tasks in emotional and non-emotional contexts with simultaneous electroencephalography recordings. The behavioral findings showed that adults had faster response speed and better conflict control performance compared to children. Children's accuracy was affected by the emotional context, whereby children had a lower accuracy in the emotional contexts compared to the non-emotional contexts. Adults had similar performances in both contexts. During the neural processes of conflict detection and conflict resolution, children had longer N2 latencies for conflict detection, and devoted more neural efforts with larger P3 amplitudes to execute resolution control on the conflicts than adults. Moreover, both age groups' reaction times (RT) were shorter in the Simon task than in the Stroop task in the non-emotional context, while, RTs were longer in the Simon task than in the Stroop task in the emotional context. Children showed larger P3 responses in the Simon task than in the Stroop task in the emotional contexts, while adults showed no such differences. The current findings demonstrate that children have immature neurodevelopment of conflict control compared to adults, and their cognitive control processes on conflicts were distracted by the emotional contexts. Children's emotional conflict control processes were also affected by the characteristic of conflict types, and they need to devote more neural effort to process Simon-like conflicts than Stroop-like conflicts compared to adults.