There is growing evidence that the superconductivity in recently discovered Sr 2 RuO 4 is isotropic p-wave. However, the definitive experiment which reveals the p-wave symmetry appears to be still lacking. Here we report some properties of the vortex state in a magnetic field parallel to the a-b plane. As is well known, the order parameter takes a simple form Δ(k) cos(θ-φ) for 0.45H c 2 <H<H c 2 where θ and φ are the angle H and k makes from the a-axis. This θ-dependence of Δ(k) can be detected by STM and the thermal conductivity tensor.