Abstract: The present healthcare system can only provide qualitative nutritional analysis for pregnant women; to address this issue, a nutritional diagram evaluation method was proposed. It integrated the information of the subject’s actual requirement of nutrients, actual intake value and the lack or excess status to formulate a quantitative assessment. The diagram of main nutrients for Chinese residents had been implemented using database technology and made possible the individualized nutritional guidance based on visualized, systematic and quantitative nutritional analysis. This algorithm has been applied in Quantitative Nutritional Guidance System and has been proved effective to pregnant women.