Experiments were conducted to know the relationships between seed quality and leakage of sugars from differently-aged seeds of rape, Chinese cabbage and radish. Seeds were artificially aged at 90% relative humidity and 45$^{circ}C$ to get different seed qualities. Significant amounts of total sugars were leaked from the dead seeds of all crops during the 8~24 hours soaking period, while high quality seeds leaked negligible amounts of total sugars. High quality seeds of all crops contained lots of sucrose and glucose and some stachyose, raffinose and fructose. During the artificial aging of seeds stachyose, raffinose, and sucrose decreased, while glucose and fructose increased.