  The power graph of finite group G is a simple graph whose vertex set is G and
two distinct elements a and b are adjacent if and only if one of them is a
power of the other. The proper power graph of G is a graph which is obtained by
deleting the identity vertex (the identity element of G). In this paper, we
improve the diameter bound of proper power graph of alternating group of degree
n which the graph is connected. We show that the diameter of An is between 6
and 11, if the n at least 51. We also describe a number of short paths in these
power graphs.
