Taking celery‘wentula’（western celery）and lettuce‘tieren’（head lettuce）as experimental materials，the growth indexs and physiology indexs of celery and lettuce seedlings at different stage were measured．Meanwhile，the rule of seedling growth at different stage and correlation with effective ccumulation temperature were studied．The results showed that celery seedling grew slowly at early stage but grew quickly later．Lettuce seedling grew quickly from the cotyledon stage to the fourth-leaf stage but grew slowly later．The chlorophyll SPAD and POD activity of celery seedlings had sustainably increased，
root activity and CAT activity firstly increased and subsequently became stable．However，in lettuce seedlings，the chlorophyll SPAD，root activity and POD activity showed the tendency of firstly increasing and subsequently decreasing，CAT activity showed a little drop and a sustainable grow，SOD activity had two peak times．Effective accumulation temperature of celery seedlings was 949.0 ℃·d with a large increase at the cotyledon stage and fifth-leaf stage．Effective accumulation temperature of lettuce seedlings was 502.9 ℃·d with a stable increase at each stage．Above all，the most appropriate planting stage for celery seedling is the fourth-leaf stage and for lettuce it is the fifth-leaf stage．