  We investigate localization properties in a two-coupled uniform chains with
quasiperiodic modulation on interchain coupling strength. We demonstrate that
this ladder is equivalent to a Aubry-Andre (AA) chain when two legs are
symmetric. Analytical and numerical results indicate the appearance of mobility
edges for asymmetric ladder. We also propose an easily engineered quasiperiodic
ladder system which is a moir\'{e} superlattice system consisting of
two-coupled uniform chains. An irrational lattice constant difference results
in quasiperiodic structure. Numerical simulations show that such a system
supports mobility edge. Additionally, we find that the mobility edge can be
detected by a dynamic method, which bases on the measurement of surviving
probability in the presence of a single imaginary negative potential as a
leakage. The result provides insightful information about the localization
transitions and mobility edge in experiment.
