  In this short note we show the following result: Let $(M^{2n+1},g)$ ($n \geq
2$) be a compact Sasaki manifold with positive transverse orthogonal
bisectional curvature. Then $\pi_1(M)$ is finite, and the universal cover of
$(M^{2n+1},g)$ is isomorphic to a weighted Sasaki sphere. We also get some
results in the case of nonnegative transverse orthogonal bisectional curvature
under some additional conditions. This extends recent work of He and Sun. The
proof uses Sasaki-Ricci flow.
