Recent research indicates that the new mothers want to learn about childrearing, and have burden in care of infants. Also it indicates that the new mothers say the lack of confidence and knowledge about infant care. This study was a prospective longitudinal reseach developing parent role education program and evaluating the effectiveness of this program for mother- infant interaction, childrearing environment and infant development. Longitudinal quasi-experimental design was used. The subjects were the healthy infants weighing over 2,500gm at birth, whose gestational age was more than 37weeks, and their mothers. The sample consisted of 19 mother-infant dyads for intervention group and 18 dyads for control group. Data were collected from March 15th to December 14th in 1999. For the intervention group received programmed education that was consisted of discharge education, telephone counselling, and home visiting for maternal education. The data were analyzed using chi-square test and t-test to test the equivalence of two groups, and the effectiveness of intervention program. This study was focused on the results of six months time point. The results were as follows: 1. There was significant difference in the mean score of mother-infant interaction(NCAST) between two groups. Intervention group showed higher scores in the subscales of sensitivity to cues, cognitive growth fostering, and caregiver total. 2. There was no significant difference in the mean score of child rearing environment (HOME) between two groups of six-month- infants. But when each subscale of HOME was examined, intervention group showed higher scores in the dimensions of opportunities for variety in daily stimulation, maternal involvement with child, and emotional, verbal response. 3. Six-month-infants of the intervention group showed significantly higher GQ in the Griffiths mental development scale. In conclusion, the maternal education program was effective in promoting the mother-infant interaction, organizing the childrearing environment, and fostering the infant development. These results were very meaningful that we found parent role education necessary for normal infants' mothers, and nurses can make a great contribution in promoting health of infants and mothers.