There are kinds of English teaching materials for preschool children in the market, including English alphabets teaching materials, word cards and picture cards. It makes no exceptions that the key learning method of these materials needs either parents or teachers¡¦ accompanies in order to teach Children to recognize alphabets and to pronounce tones, helping Children to learn alphabets. The research aims to assist Children to study English alphabets more effectively. The research methods consist of the following: to study through related documents in order to comprehend specialists¡¦ advises about children studies; to observe how the specialists using teaching methods to tutor children study alphabets; to realize users¡¦ requirements through interviews. Combining the three methods above, the researcher decides to use LEGO MINDSTORMS NXT robots and accessories as teaching tools which are low cost, similar to LEGO cubes in appearance, and with easy replace accessories. Associate with PC to transmit information, the researcher designs an assisting studying system that can help children to recognize and study alphabets and tones without parents or teacher¡¦s accompanying. The research intends to provide the follow-through children assisted study system developers as a reference through this research and develop methods, in order to speed the time of development.