Abstract In our daily life, individuals are likely to make judgments and decisions under uncertain situations. Thus, the individual is faced with the uncertain risk to gain or to lose during the process of making the decisions. Children’s risk decision affects their life and learning, the risk decision made by the children in their experiment situation and the framing effect can well predict children’s risky decisions and behavior in their real life, but the study about this is hard to see in our country. Therefore, the purpose of the study is to discuss the development character of the risk decision under the effect of task framework and confidence on the risky decision made by children from different grade. In the research we used the between-group design of 3 (Grade: grade two/ four/ six)×2 (task framework: gains/ losses)×2 (confidence level: overconfidence/ under confidence), according to the method of random sampling to choose 59 people in grade two as same as in grade four and grade six, We investigated the development characteristics of the risky decision made by 177 children. The participants accomplished five situational experiment tasks alone according to the instructions with the guidance of the experimenters, reported his own confidence level. MANOVA were conducted by SPSS13.0 statistical software to analyse the collected data . Here are the results: (1) Children of different grades show significant difference in conservative decision (F=3.207,p＜.05,η2=.036,1-β=.581), risk decision (F=3.034,p＜.05,η2=.038,1-β=.606) and preference shift (F=3.122,p＜.05,η2=.037,1-β=.594), the further multiple comparisons found that children from grade two have lower score in conservative decision than children from grade six (p＜.05), but the situation is just the other way around when it comes to the risk decision (p＜.05) and the preference shift (p＜.05), however, the difference between grade two and grade four is not significant (p＞.05) and so is grade four (p＞.05) and grade six (p＞.05); (2) Under different task framework, the conservative strategy under benefit framework is far more higher than the loss framework (F=22.422,p＜.01,η2=.120,1-β=.997), however, the risk strategy is lower (F=22.911,p＜.01,η2=.123,1-β=.997), the score of risk preference shift is obviously lower (F=22.680,p＜.01，η2=.121,1-β=.997); (3) Risky decision (F=1.186,p＞.05,η2=.007,1-β=.191), conservative decision (F=1.078,p＞.05,η2=.007,1-β=.178) and preference shift (F=1.132,p＞.05,η2=.007,1-β=.185) made by children with different confidence level is of no significant difference. The interaction of confidence level and grade on children’s conservative decision, risk decision and preference shift is not significant difference, and so as the confidence level and task framework, grade and task framework (p＞.05). The main conclusions of the present study are as follows : (1) Children in different grades show different development tendency in risk decision, the younger children of grade two are more likely to take risks than the older children of grade six, grade four is a critical period during the development period of risk decision; (2) The framing effect appears in children’s risk decision shows the phenomenon of preference shift under the gain framework and loss framework; (3) Confidence level show no effect on children’s risk decision.