  We report the production of $^{39}$K and $^{87}$Rb Bose-Einstein condensates
(BECs) in the lowest hyperfine states $| F=1,m_{F}=1 \rangle$ simultaneously.
We collect atoms in bright/dark magneto-optical traps (MOTs) of
$^{39}$K/$^{87}$Rb to overcome the light-assisted losses of $^{39}$K atoms.
Gray molasses cooling on the D1 line of the $^{39}$K is used to effectively
increase the phase density, which improves the loading efficiency of $^{39}$K
into the quadrupole magnetic trap. Simultaneously, the normal molasses are
employed for $^{87}$Rb. After the microwave evaporation cooling on $^{87}$Rb in
the optically plugged magnetic trap, the atoms mixture is transferred to a
crossed optical dipole trap, where the collisional properties of the two
species in different combinations of the hyperfine states are studied. The dual
species BECs of $^{39}$K and $^{87}$Rb are obtained by further evaporative
cooling in optical dipole trap at a magnetic field of 372.6 G with the
background repulsive interspecies scattering length $a_{KRb}$ = 34 $a_{0}$
($a_{0}$ is the Bohr radius) and the intraspecies scattering length $a_{K}$ =
20.05 $a_{0}$.
