Abstract: Rockwool and nutrient soil blocks were used for the substrates of the cultivating seedlings of tomatoes. Effects of two cultural substrates on tomato seedlings were observed. The results indicated that increments of seedlings on rockwool culture were lower than those on nutrient soil culture on dry weight of shoot-leaves, leaf area and shoot height during 24 days after seed sowed. However after 24 days,increments of the shoot-leaves,leaf area and shoot height on rockwool culture were much more than those on nutrient soil culture. Root dry weight on rockwool culture was weightier than that on nutrient soil culture during the cultivating seedlings of tomatoes. Rockwool as a substrate is better for cultivating tomato seedling.