  This paper concerns a controllability problem for blowup points on heat
equation. It can be described as follows: In the absence of control, the
solution to the linear heat system globally exists in a bounded domain
$\Omega$. While, for a given time $T>0$ and a point $a$ in this domain, we find
a feedback control, which is acted on an internal subset $\omega$ of this
domain, such that the corresponding solution to this system blows up at time
$T$ and holds unique point $a$. We show that $a\in \omega$ can be the unique
blowup point of the corresponding solution with a certain feedback control, and
for any feedback control, $a\in \Omega\setminus \overline{\omega}$ could not be
the unique blowup point.
