  This paper is concerned with semi-linear backward stochastic partial
differential equations (BSPDEs for short) of super-parabolic type. An
$L^p$-theory is given for the Cauchy problem of BSPDEs, separately for the case
of $p\in (1,2]$ and for the case of $p\in (2, \infty)$. A comparison theorem is
also addressed.
