Objective To evaluate the effectiveness of an activity of nutrition science experience on nutrition and food safety cog-nition among primary and secondary school students .Methods With stratified cluster sampling ,students of grade 5 and 6 in one primary school and students of grade 1 and 2 in one middle school in Chongqing were selected ,and randomly divided into interven-tion group(n= 501) and control group(n= 522) .Only conducted the activity in the intervention group .Baseline data of all the students were investigated before the intervention .Effect evaluation was performed instantly in the intervention group and control group ,and a follow-up survey carried out in the intervention group after 9 months(n= 472) .Results The nutrition knowledge scores of instant intervention group were 9 .03 ± 2 .75 and 14 .70 ± 3 .28 before and after intervention respectively (U=29 .78 ,P<0 .01);the knowledge scores of the nine months later intervention group were 12 .35 ± 2 .89 ,which were lower than instant interven-tion group(U=12 .40 ,P<0 .01) ,but higher than before intervention(U=18 .04 ,P<0 .01) .The food safety scores of instant inter-vention group ,which were higher than control group ,nine months later intervention group and before intervention(P<0 .01) .Con-clusion It is feasible and effective to conduct a nutrition science experience among primary and secondary school students .