Taking tomato variety‘Yingfen No.8’as test material，this paper used peat and vermiculite as mixed matrix to study in tidal irrigation and under intelligent greenhouse condition the effects of nutrient supplying maintaining time and interval time on quality of tomato seedlings raised on trays with central composite rotatable designs of 2 factors．The results showed when tomato grew 5 leaves and 1 heart，with the increase of nutrient supplying time，the seedling dry matter and strong seedling index showed first increasing then declining trend．While along with the interval time extension of nutrient supplying，the seedling dry matter and strong seedling index showed a declining tendency．The optimal nutrient supplying scheme is in 8-18 min of maintaining time and 198-348 min of interval time．Thus the seedling quality could achieve an ideal situation．We believe under the experiment condition，this solution is the best water and fertilizer supplying scheme．