Identifying regulatory gene interactions is inherently challenging as it depends on both the transcriptional and epigenetic landscapes. Multiple methods are proposed to infer gene regulatory networks (GRNs) using single-cell multi-omics data, yet the absence of a standardized benchmarking framework remains an obstacle to unbiased performance evaluation. Here we present BEAR-GRN, a systematic resource providing standardized datasets, curated ground-truth networks, and a unified computational pipeline for benchmarking GRN inference methods. Using BEAR-GRN, we assess state-of-the-art multi-omics GRN inference methods across paired single-cell RNA-seq and ATAC-seq datasets spanning human and mouse cell types. We evaluate accuracy against four complementary ground-truth definitions, alongside computational efficiency, output stability, and modality contribution. Although ground-truth choice profoundly influences performance, LINGER and DIRECT-NET show the highest overall accuracy and stability. Modality perturbation experiments reveal that current methods are predominantly RNA-driven, with chromatin accessibility contributing limited independent signal. BEAR-GRN enables researchers to evaluate existing and new GRN methods against established baselines. BEAR-GRN provides a standardized framework for benchmarking gene regulatory network inference methods using single-cell multi-omics data, revealing that ground-truth choice profoundly impacts performance and that current methods remain predominantly RNA-driven.