In order to study the effect of sowing in different seasons on the content of nutritional functional components in barley grass powder and grains， and to explore the high-efficient production technology of high-quality dual-purpose barley， 48 barley varieties （lines） from Yunan province were sown in four seasons （spring， summer， autumn and winter） for two consecutive years. The samples harvested were subjected to measure the contents of total flavones， GABA， alkaloids and proteins by spectrophotometry and Kjeldahl method， followed by the correlation analysis on the nutrient function components between barley grass powder and grains. The results showed that samples harvested from different years and seasons showed a significant difference on the accumulation of nutritional functional components in barley grass powder and grains. The average contents of the four nutritional functional components （total flavones， GABA， alkaloids and proteins） in grass powder were autumn sowing > winter sowing > spring sowing > summer sowing. These components in grains from winter sowing season were higher than those in grains from autumn sowing season. In general， the nutritional functional components of grass powder was higher than those of the grains. The nutrient functional components were greatly affected by the sowing season， showing the trend of sowing season > varieties > varieties × sowing season. As a result， excellent dual-purpose barley varieties （Aisi 4， Tengyun 4 and Yunpi 22） were preliminarily selected.