Abstract: Abstract: The trial with peat and vermiculite (V:V=2:1) as growing media, adding different amount of cow manure compost was carried out in order to study the effect of different amount of maturity cow manure compost on the seedling growth of tomato and melon. The result showed that: with different amount of added maturity cow manure compost, the bulk density, pH value, electrical conductivity, the organic matter content of growing media increased by 15%~70%, 3.7%~33.3%, 62.1%~259%, 8.5%~81.9% respectively. But total porosity reduced by 1.7%~12.9% obviously. In a certain range, with an increase of amount of cow manure compost, the melon seeding growth increased, but the tomato seedling showed opposite symptoms. As compared with adding 25% cow manure compost in growing media, in treatment T3 (adding 15% cow manure compost) the stem diameter, height, dry weight, root/shoot ratio of melon increased by 24.1%, 26.7%, 21.1%, 10.6% respectively; and in treatment T1 (adding 5% cow manure compost) the stem diameter, height, dry weight of tomato increased by 23.5%, 9.3%, 36.4%, 3.9% respectively.