The tremendous amount of data generated by largescale, parallel scientific and engineering simulations make the analysis and archiving of this data difficult. To address this problem, in previous work, we developed an efficient archival scheme based on the functional representation of simulation data — this approximation scheme can significantly reduce storage requirements. However, common visualization tools such as the marching cubes algorithm for isosurface generation cannot be directly applied with this data representation. Thus, in this paper we propose a new, efficient isosurface visualization algorithm that takes full advantage of the functional approximation of simulation data. This method is fundamentally different from the marching cubes approach in that the visualization of isosurface is achieved through the solution of sets of ordinary differential equations. We present computational results detailing the effectiveness of this new approach for a simulation modeling the fluid dynamics of a turbulent reacting flow. The results demonstrate that the method is efficient in a parallel environment and represents a promising approach for the visualization of isosurface in simulation data from large-scale scientific applications.