Biological nanochannels made from proteins play a central role in cellular signalling(1-9). The rapid emergence of DNA nanotechnology in recent years(10-13) has opened up the possibility of making similar nanochannels from DNA. Building on previous work on switchable DNA nanocompartment(14,15), We have constructed complex DNA nanosystems to investigate the gating behaviour of these nanochannels. Here we show that DNA nanochannels can be gated by stress exerted by permeating solute particles at non-equilibrium states due to the high flexibility of the nanochannels. This novel gating mechanism results in tunable ratchet-like transport of solute particles through the nanochannels. A simple model that couples non-equilibrium channel gating with transport flux can quantitatively explain a number of the phenomena we observe. With only one set of model parameters, we can reproduce diverse gating behaviours, modulated by an inherent gating threshold. This work could lead to the development of new devices based on DNA nanochannels.