  Recent many physicists suggest that the dark energy in the universe might
result from the Born-Infeld(B-I) type scalar field of string theory. The
universe of B-I type scalar field with potential can undergo a phase of
accelerating expansion. The corresponding equation of state parameter lies in
the range of $\displaystyle -1<\omega<-{1/3}$. The equation of state parameter
of B-I type scalar field without potential lies in the range of
$0\leq\omega\leq1$. We find that weak energy condition and strong energy
condition are violated for phantom B-I type scalar field. The equation of state
parameter lies in the range of $\omega<-1$.
