Marigold is one of the most important ornamental plants, that cultured as cut flower and edge plants. In this study anatomical and morphological traits, and also earliness of marigold transplants were examined. Treatments were 350µmol mol-1 (as control), 700, 1050 and 1400µmol mol-1 CO2. Each treatment had 3 replications, and the statistic was randomized complete design (RCD). In this experiment, 14 traits were studied. These traits were: diameter of stem, number of leaves, high of stem, chlorophyll rate, stomatal density, epiderm cell density, stomatal index, stomatal length and width, stomatal size, guard cell length and width, leaf area total and air dry weight. Results of analysis showed, that all traits were affected by high level of CO2. But CO2 at 700µmol mol-1 had highest effects on the traits. The mean of stem diameter (69%) and plant height (2 times) increased in compared to control at 700µmol mol-1. The leaves number, stomatal density, epidermal cells, length and size of stomatal, length of cell guard, total of leaf area and dry weight of plants increased at highest level of CO2. The flowering of plants accelerated about 15 – 20 days, than control at 700µmol mol-1 CO2

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