Electromagnetic radiation has become a severe problem due to the widespread utilization of wireless communications and smart electronic devices. Hence, the development of high-performance electromagnetic wave absorbers to overcome the electromagnetic pollution is of utmost significance. Herein, density functional theory (DFT) calculations are adopted to guide the design of high-performance electromagnetic wave absorbers based on layered MoS2. The results indicate that the electronic properties, the dipole moment and the electric polarization of vertically-aligned MoS2 monolayers on N-doped graphene are significantly tuned compared to horizontally-aligned MoS2 monolayers on N-doped graphene and MoS2 nanosheets, favoring the absorption of electromagnetic waves. Based on theoretical predictions, we have combined vertically-aligned MoS2 monolayers and N-doped graphene nanomesh by the spatial confinement effect of the nanomeshs. The experimental results demonstrate that the MoS2 monolayers on N-doped graphene exhibit excellent electromagnetic wave absorption performance with a minimal reflection loss of –72.83 dB and an effective absorption bandwidth of 4.81 GHz even at a matching thickness below 2.0 mm, remarkably outperforming MoS2 nanosheets. The excellent consistency between theoretical and experimental results highlights that the DFT calculations can be employed as a design tool for high-performance electromagnetic wave absorber. Based on the excellent electromagnetic absorption performance of the MoS2 monolayers, a highly sensitive wireless pressure micro-sensor is designed, which has potential apllication in internet of things.