Moire fringe patterns created by stacking different 2D layered materials as artificial van der Waals (vdW) heterostructures have become a novel platform to study and engineer optically generated excitonic properties. The moire patterns contribute to the formation of spatially ordered excitonic states (excitons and trions), which can be used in the quantum simulation of many-body systems and ensembles of coherent quantum light emitters. The intriguing moire excitonic properties are affected by and controlled via the interaction with magnetic elements. Here, a moire excitonic system interacting with the magnetic elementary excitation of antiferromagnetic orders in MoSe2/MnPS3 vdW heterostructures is reported. The low-temperature photoluminescence spectra with additional fine spectral structures on the low-energy side, which are coupled magnon-trion peaks below the Neel temperature of MnPS3, are carefully investigated. The fine spectral structures with long lifetime and coherence time are assigned to intralayer trion-magnon complexes trapped in the moire potentials (moire trion-magnon complexes). These findings highlight the emergence of moire trion-magnon complexes and provide a new way to explore novel quantum phenomena in moire excitonic systems with magnetic functionalities.