English has been presented as one of extra curricular subjects in kindergarten. The main English lesson given is simple vocabularies. Mnemonic skill such as keyword is known as an effective method to improve memory ability. The research tried to find the effectiveness of keyword method to improve the subjects’ memory on English vocabularies. The 20 subjects aged 5-7 years old and divided into two groups. Using the Mann-Whitney analysis and Post Test Only Control Group Design, it was found that the experiment group showed significantly better memory ability. Mnemonics effectiveness and memory ability are discussed further in the article.