DCPTA(2-diethylaminoethyl-3, 4-dichlorophenylether) is a new plant regulator which can be used to regulate growth and development for crops. Experiments on maize seedlings were conducted in the growth chamber to study the effects of foliar applied DCPTA. The plant pots were placed in a completely randomized design with three replicates. The maize seedlings were treated with 0 mg · L-1(control), 20 mg · L-1 and 40 mg · L-1 DCPTA solution. The effects of DCPTA on the photosynthetic characteristics(photosynthesis, stomata conductance, intercellular CO2, and transpiration rate), related physiological characteristics(contents of soluble sugar and starch), chlorophyll fl uorescence parameters(Fo, Fm, Fv/Fm, Fv/Fo, qP, and qN) and the weight of dry matter in maize seedling were studied. The results showed that DCPTA enhanced photosynthesis of maize seedling. In general, photosynthetic rate in leaves was significantly promoted through spraying DCPTA solution, and 40 mg · L-1 DCPTA was found to be the best concentration for maize. The relationship between stomata conductance and transpiration rate in maize leaves could be described as linear. With regard to the chlorophyll fl uorescence parameters, our fi ndings showed that 40 mg · L-1 DCPTA in maize seedling caused an increase in Fm, Fv/Fm, Fm/Fo, qP and a decrease in Fo and qN at some time points checked. It is suggested that DCPTA increased photosynthetic rate by raising both the content of chlorophyll and activities of PSII and the contents of sugar and starch. Compared with the control, the treated maize seedling caused an increase in plant height, root length, shoot dry mass, root dry mass, or the total(root plus shoot) dry mass. Experiments on maize seedlings were conducted in the growth chamber to study the effects of foliar applied DCPTA. The plant pots were placed in a completely randomized design with three replicates. The maize seedlings were treated with 0 mg · L-1 (control), 20 mg · L-1 and 40 mg · L -1 DCPTA solution. The effects of DCPTA on the photosynthetic characteristics (photosynthesis, stomata conductance, intercellular CO2, and transpiration rate), related physiological characteristics (contents of soluble sugar and starch), chlorophyll florescence parameters (Fo, Fm, Fv / Fm, Fv / Fo, qP, and qN) and the weight of dry matter in maize seedling were studied. The general results are that DCPTA enhanced photosynthesis of maize seedling. In general, photosynthetic rate in leaves was promoted by spraying DCPTA solution, and 40 mg · L-1 DCPTA was foun The relationship between stomata conductance and transpiration rate in maize leaves could be described as linear. With regard to the chlorophyll fl uorescence parameters, our fi ndings showed that 40 mg · L-1 DCPTA in maize seedling caused an increase in Fm, Fv / Fm, Fm / Fo, qP and a decrease in Fo and qN at some time points checked. It is suggested that DCPTA increased photosynthetic rate by raising both the content of chlorophyll and activities of PSII and the contents of sugar and starch. Compared with the control, the treated maize seedling caused an increase in plant height, root length, shoot dry mass, root dry mass, or the total (root plus shoot) dry mass.