For soft-mode turbulence, which is essentially the spatiotemporal chaos caused by the nonlinear interaction between convective modes and Goldstone modes in electroconvection of homeotropic nematics, a type of order-disorder phase transition was revealed, in which a new order parameter was introduced as pattern ordering. We calculated the spatial correlation function and the anisotropy of the convective patterns as a 2D XY system because the convective wave vector could freely rotate in the homeotropic system. We found the hidden order in the chaotic patterns observed beyond the Lifshitz frequency f(L), and a transition from a disordered to a hidden ordered state occurred at the f(L) with the increase of the frequency of the applied voltages.