  The twist angle {\gamma} dependence of the Josephson critical current of
d-wave superconductors in one junction and a granular system is considered. Our
results show that the twist angle {\gamma} dependence of the d-wave Josephson
critical current is the same for one junction and a granular system. The
magnetic field dependences of the critical-current of a granular d-wave
superconductor has also been determined by considering the rectangular and
circular junction model of an array of small superconducting particles which
interacting by Josephson coupling through insulating barriers. We will show
that in the case of circular model, the critical current of the Josephson
current is larger than that of rectangular one.
