Three-dimensional waffle-like metacomposite (3DWM) composed of ferromagnetic microwires is proposed with the aim of integrating structure and microwave absorption performance. The metamaterial units were formed by weaving the ferromagnetic microwires into certain pattern along with the quartz fiber substrate, making it a layer-by-layer integral structure without delamination. Based on the significance of angle arrangement of ferromagnetic microwires on the electromagnetic response during the rotation of metacomposite in practical application, this study conducted experiment and simulation considering different angle arrangements ranging from 90° to 165° to reveal their electromagnetic response characteristics and microwave absorption mechanism within X and Ku bands. It has been found that the arrangement angle of ferromagnetic microwire can adjust the complex permittivity. The dielectric loss of 3DWM was mainly originated from multiple Debye relaxation process and the primary magnetic loss came from eddy current loss and exchange resonance. The threshold angle was found to be 135°, within which the improvement of impedance matching led to the enhancement of microwave absorption. In addition, the angle arrangement of ferromagnetic microwire affected the direction of electric and magnetic fields, which determines the dielectric loss and magnetic loss mechanisms. The 3DWM proposed in this study is promising in adjusting electromagnetic response of microwaves as a radar absorbing material in engineering applications.