A fully explicit gas-liquid two-phase flow solver based on weakly compressible assumption with interface-adapted AMR method is proposed to avoid solving pressure Poisson equation for large-scale two-phase flow simulations. To capture the gas-liquid interface, the conservative Allen-Cahn equation, which is one of the phase-filed models, is solved by finite-volume method with continuum equation. The AMR method greatly reduces the computational cost by assigning high-resolution mesh to the region around the moving interface. We have developed the GPU-code of the tree-based AMR and the allocation, deallocation and defragmentation of device memory are performed in own code to improve computational efficiency. Several benchmarks are examined and the results of weakly compressible scheme are in good agreement with the experimental and computational references by using semi-implicit incompressible solver. We successfully have carried out two-phase flow simulations including very thin liquid film by using less grid points compared with that of uniform grid system.