  Neutral pions have been measured in $^3$He+Au collisions at
$\sqrt{s_{_{NN}}}$=200 GeV up to 20 GeV/$c$ in the RHIC Year-2014 run. The
nuclear modification factor $R_{\rm AA}$ was measured and compared with that
from $d$+Au collisions. The integrated $R_{\rm AA}$ as a function of $N_{\rm
part}$ was calculated for $d$+Au, $^3$He+Au and Au+Au collisions at
$\sqrt{s_{_{NN}}}$=200 GeV, and found to converge for $N_{\rm part}>$12, while
a clear system ordering $R_{\rm dAu}$$>$$R_{\rm HeAu}$$>$$R_{\rm AuAu}$ was
observed for $N_{\rm part}<$12. The fractional momentum loss for the most
central $^3$He+Au collisions was also estimated.
