The integration of millimeter wave (mmWave) and multiple-input and multiple-output (MIMO) techniques has been designed to provide reliable communications with large degrees of freedom while supporting the explosively growing number of mobile users. Under stringent requirements in terms of latency and reliability, due to the infinite blocklength requirement of the Shannonâ™s theorem, researchers have investigated new methods to characterize the wireless data transmissions considering the block error probability. The finite blocklength coding (FBC) technique has been developed to model the finite blocklength coding rate in the non-asymptotic regime while supporting short-packet communications over 5G wireless ad- hoc networks. However, because of the design complexity when characterizing the second-order coding rate over mmWave MIMO based wireless channels while being integrated with FBC, how to accurately derive the finite blocklength coding rate over the mmWave MIMO wireless fading channels is still an open problem over 5G wireless ad-hoc networks. To tackle the above- mentioned challenges, we propose and develop the system model which can efficiently integrate the mmWave-MIMO techniques with the finite blocklength coding over 5G wireless ad-hoc networks. In particular, we derive the system equations which characterize the foundational information-theoretical relationship between the finite blocklength channel capacity and the coding rate measures over our proposed mmWave MIMO based 5G wireless ad-hoc networks in the finite blocklength regime. Also conducted is the MATLAB-based performance evaluation results, which validate and analyze our proposed schemes over mmWave MIMO based 5G wireless ad-hoc networks in the finite blocklength regime.