Nuclear localization of cytoplasmic RNA virus proteins mediated by intrinsic nuclear localization signal (NLS) plays essential roles in successful virus replication. We previously reported that NLS mutation in the matrix (M) protein obviously attenuates the replication and pathogenicity of Newcastle disease virus (NDV), but the attenuated replication mechanism of NDV remains unclear. In this study, we showed that M/NLS mutation not only disrupted M’s nucleocytoplasmic trafficking characteristic but also impaired viral RNA synthesis and transcription. Using TMT-based quantitative proteomics analysis of BSR-T7/5 cells infected with the parental NDV rSS1GFP and the mutant NDV rSS1GFP-M/NLSm harboring M/NLS mutation, we found that rSS1GFP infection stimulated much greater quantities and more expression level changes of differentially expressed proteins involved in host cell transcription, ribosomal structure, posttranslational modification, and intracellular trafficking than rSS1GFP-M/NLSm infection. Further in-depth analysis revealed that early nuclear localization of M protein inhibited cell transcription and participated in reducing cellular protein synthesis, posttranscriptional modification and transport; whereas later cytoplasmic localization of M protein promoted viral protein synthesis and benefited for virus assembly and budding. Importantly, we first demonstrated that later cytoplasmic localization of M protein effected the inhibition of TIFA expression in a dose-dependent manner, and inhibiting TIFA expression was beneficial to NDV replication by down-regulating TIFA/TRAF6/NF-κB-mediated production of cytokines. Our findings suggest that precocious cytoplasmic localization of M protein caused by M/NLS mutation disrupts these important biological processes, and thereby causes the attenuated replication of NDV, demonstrating that NDV replication is closely related to the nucleocytoplasmic trafficking of M protein.