and magnetic reconnection played an important role in these transport processes. In the levitation model, cool plasma is lifted by rising magnetic fields at the PIL, which resides in the upward concavities of the helical field (magnetic dips structure). In the evaporation-condensation model, chromospheric plasma is evaporated and flow up driven by heating localized nearby the footpoint, which ultimately condenses in the corona as cool prominence mass. Due to the limitation of the observation, it is still controversial on these three models. In other words, poor observational evidence makes it difficult for us to understand fully the mechanism of filament mass supply.

In order to understand the formation of the filament, we study the formation process of an active region filament in NOAA 11903 observed by *Solar Dynamics Observatory* and New Vacuum Solar Telescope during the period from 02:00 to 10:00 on November 25, 2013. We mainly investigate the material injection process of the filament. The sections of this paper are organized as follows: the observations and methods are described in Section \[sec:obser methods\], the results are presented in the Section \[sec:results\], and the main conclusion and discussion are given in Section \[sec:conclusion\].

Observations and Methods {#sec:obser methods}
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Observations
