We propose N=4 twisted superspace formalism in four dimensions by introducing
Dirac-Kahler twist. In addition to the BRST charge as a scalar counter part of
twisted supercharge we find vector and tensor twisted supercharges. By
introducing twisted chiral superfield we explicitly construct off-shell twisted
N=4 SUSY invariant action. We can propose variety of supergauge invariant
actions by introducing twisted vector superfield. We may, however, need to find
further constraints to identify twisted N=4 super Yang-Mills action. We propose
a superconnection formalism of twisted superspace where constraints play a
crucial role. It turns out that N=4 superalgebra of Dirac-Kahler twist can be
decomposed into N=2 sectors. We can then construct twisted N=2 super Yang-Mills
actions by the superconnection formalism of twisted superspace in two and four
dimensions.Comment: 62page