Vertical drains are usually installed in subsoil consisting of several layers, Due to the complex nature of the problem, over the past decades, the consolidation properties of multi-layered ground with vertical drains have been analysed mainly by numerieal methods. An analytical solution for consolidation of double-layered ground with vertical drains under quasi-equal strain condition is presented in this paper. The main steps for the computation procedure are listed. The convergence of the series solution is discussed. The comparisons between the results obtained by the present analytical method and the existing numerical solutions are described by figures. The orthogonal relation for the system of double-layered ground with vertical drains is proven. Finally, some consolidation properties of double-layered ground with vertical drains are analysed. Copyright