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For the first time, we statistically study the properties of ephemeralregions (ERs) and quantitatively determine their parameters at the emergencestage based on a sample of 2988 ERs observed by the \emph{Solar DynamicsObservatory}. During the emergence process, there are three kinds of kinematicperformances, i.e., separation of dipolar patches, shift of ER's magneticcentroid, and rotation of ER's axis. The average emergence duration, fluxemergence rate, separation velocity, shift velocity, and angular speed are 49.3min, 2.6 $\times$ 10$^{15}$ Mx s$^{-1}$, 1.1 km s$^{-1}$, 0.9 km s$^{-1}$, and0$\degr$.6 min$^{-1}$, respectively. At the end of emergence, the mean magneticflux, separation distance, shift distance, and rotation angle are 9.3 $\times$10$^{18}$ Mx, 4.7 Mm, 1.1 Mm, and 12$\degr$.9, respectively. We also find thatthe higher the ER magnetic flux is, (1) the longer the emergence lasts, (2) thehigher the flux emergence rate is, (3) the further the two polarities separate,(4) the lower the separation velocity is, (5) the larger the shift distance is,(6) the slower the ER shifts, and (7) the lower the rotation speed is. However,the rotation angle seems not to depend on the magnetic flux. Not only at thestart time, but also at the end time, the ERs are randomly oriented in both thenorthern and the southern hemispheres. Besides, neither the anticlockwiserotated ERs, nor the clockwise rotated ones dominate the northern or thesouthern hemisphere.

Properties of Solar Ephemeral Regions at the Emergence Stage