  Here we present the results of a wide-field (~36 sq. deg.) near-infrared
(ZYJHK) survey of the Praesepe cluster using the Data Release 9 of the UKIRT
Infrared Deep Sky Survey Galactic Clusters Survey. We selected cluster
candidates of Praesepe based on astrometry and photometry. With our candidate
list, we have obtained the luminosity function of Praesepe in the Z and J
bands, and we have derived the mass function of Praesepe from 0.6 down to 0.072
Msol. Moreover, we have estimated the binarity of the Praesepe members in the
0.45-0.07 Msol mass range and as well as their variability.
