Space-based detectors will open the millihertz band to survey . (VBs) is a key to verifying the performance of space-based detectors because its parameters are known from electromagnetic observations and it is expected to be a detectable source of . We evaluated 73 VBs, computing their detection prospects and parameter estimation precision for individual detectors and networks. Among single detectors, DECIGO shows the highest sensitivity, detecting 71 sources at signal-to-noise ratio $\rho$ $\ge$ 5, compared to 42 for LISA, 32 for Taiji, and 27 for TianQin, while the full TianQin + LISA + Taiji + DECIGO network improves this to 73 detectable sources. For parameter estimation, individual detectors achieve median precisions on the order of $\sim {10}^{-2}-{10}^{-1}{\mathrm{\text{M}}}_{\odot }$ for chirp mass, $\sim 1\mathrm{\text{kpc}}$ for distance, $\sim 1-17\mathrm{\text{deg}}$ for inclination and $\sim {10}^{-4}-{10}^{-2}{\mathrm{\text{deg}}}^2$ for sky localization. The complete TianQin + LISA + Taiji + DECIGO network enhances these constraints substantially, reducing the median uncertainties to approximately $\sim {10}^{-2}{\mathrm{\text{M}}}_{\odot }$ in chirp mass, $\sim {10}^{-2}\mathrm{\text{kpc}}$ in distance, $\sim 1\mathrm{\text{deg}}$ in inclination and $\sim {10}^{-4}{\mathrm{\text{deg}}}^2$ in sky localization. The upcoming space-based detectors, especially their networks, have outstanding observational capabilities for , which will advance our research on multi-messenger astronomy and deepen our understanding of in the Milky Way. Space-based detectors, such as TianQin, LISA, Taiji, and DECIGO, will open the millihertz frequency band, promising to detect tens of thousands of Galactic . Among these, , which are systems already observed electromagnetically, are crucial for validating detector performance. Our results demonstrate that among single detectors, DECIGO offers the highest detection sensitivity, identifying 70 sources at $\ge$ 5, followed by LISA with 41, Taiji with 31, and TianQin with 26. In parameter estimation, DECIGO provides the best median sky localization precision with $\sim 3.9\times {10}^{-3}{\mathrm{\text{deg}}}^2$, but exhibits larger average uncertainties for chirp mass and distance due to its sensitivity to fainter populations. Taiji achieves the tightest constraints on chirp mass with median ${\sigma }_{ℳ}=1.47\times {10}^{-2}{\mathrm{\text{M}}}_{\odot }$ and distance with median ${\sigma }_d=0.172\mathrm{\text{kpc}}$. However, multi-detector networks (e.g., TianQin+LISA+Taiji+DECIGO) significantly enhance the detection count, especially for faint sources, and dramatically improve parameter estimation. For instance, such a network can localize sources to $\sim {10}^{-5}{\mathrm{\text{deg}}}^2$ and measure chirp masses with $$0.01% precision for high-SNR systems like J0806. This work underscores the scientific necessity of operating a coordinated network of space-based observatories to maximize the scientific return from Galactic binary populations.