  We apply the Statefinder diagnostic to the Modified Polytropic Cardassian
Universe in this work. We find that the Statefinder diagnostic is quite
effective to distinguish Cardassian models from a series of other cosmological
models. The $s-r$ plane is used to classify the Modified Polytropic Cardassian
models into six cases. The evolutionary trajectories in the $s-r$ plane for the
cases with different $n$ and $\beta$ reveal different evolutionary properties
of the universe. In addition, we combine the observational $H(z)$ data, the
Cosmic Microwave Background (CMB) data and the Baryonic Acoustic Oscillation
(BAO) data to make a joint analysis. We find that \textbf{Case 2} can be
excluded at the 68.3% confidence level and any case is consistent with the
observations at the 95.4% confidence level.
