Abstract: This study proposes an asynchronized-type parallel double-stage shear plate damper (APDSPD). The APDSPD consists of two first shear steel plates and one second shear steel plate in parallel. It is anticipated that the APDSPD will demonstrate an asynchronized-type double-stage working mechanism. To validate the feasibility of the APDSPD and to reveal its asynchronized-type double-stage working characteristics, two test specimens were designed, manufactured, and tested under the pseudo static load. The geometric and material properties of the shear steel plates were selected as test variables. The experimental results indicated that the APDSPD proposed successfully achieved its anticipated double-stage working mechanism. In the first stage, the mechanical properties of the APDSPD were provided by the first shear steel plate while the load-transfer bolts to slide freely within slotted holes. In the second stage, the mechanical properties of the APDSPD were provided by the first and second shear steel plates while load-transfer bolts contact with slotted holes. Refined numerical simulations were conducted using Abaqus software, and pertinent computational results were compared with the experimental results. The test and simulated results agreed well. The hysteretic characteristics and asynchronized-type double-stage working characteristics of APDSPD were further revealed. This study can provide a reference for the research and design of double-stage shear dampers.