In this paper, we investigated the output characteristics of the electron bunch accelerated by a chirped femtosecond laser pulse in vacuum using linear, elliptical and circular polarization states. To examine the features of the energy and angular spectra, emittances and position distribution of the electron bunch numerically, 105 electrons are used . It is found that the initial emittances of the electron bunch together with a proper choice of the polarization state of the laser pulse could lead to the efficient electron bunch acceleration
