For us adults, it is beyond reproach to know the influence of hand washing on human health. However, for children who are not deeply involved in the world and have weak ability to distinguish right from wrong, their parents force them to develop good washing habits, and there may be many doubts in their hearts. But empty preaching can't arouse children's interest in washing their hands frequently. Therefore, according to the cognitive characteristics of children's thinking in images, our parents can use modern educational means to play the role of network platform and download some pictures and videos about bacteria, so that children can realize that although our baby's little hands look white and clean, there are many things like bugs-bacteria condensed on them. These things can only be seen in a scientific instrument called a microscope. Take this opportunity to let children see some photos or videos of many children getting sick and getting injections because of careless personal hygiene, so as to enrich their knowledge of health science. Invisible, health awareness and frequent hand washing will leave a deep imprint on children's minds.