The orbit of Pluto is unusual in several ways. Pluto's orbit is very unusual. At times it is closer to the Sun than Neptune (as it was from January 1979 to February 11 1999). Pluto rotates in the opposite direction from most of the other planets. You may be wondering why Pluto doesn't crash with Neptune, since their orbits are so close. This is because their orbits are in control. Pluto orbits the Sun twice for every 3 orbits of Neptune. As a result, Pluto and Neptune are never very close to each other.

Pluto's orbit is tilted more than 17° from the ecliptic. The orbit is also very abnormal (it's far from being circular) than any other planetary orbit.
Here is a diagram on the planets orbit:

Every 228 years, Pluto's orbit brings it closer to the Sun than Neptune does for a period of 20 years (Pluto take 248 "earth-years" to orbit the sun once). From 1979 to March 1999, Neptune was the farthest planet from the Sun.