Molecular jets are seen coming from the youngest protostars in the early phase of low-mass star formation. They are detected in CO, SiO, and SO at (sub)millimeter wavelengths down to the innermost regions, where their associated protostars and accretion disks are deeply embedded and where they are launched and collimated. They are not only the fossil records of accretion history of the protostars but also are expected to play an important role in facilitating the accretion process. Studying their physical properties (e.g., mass-loss rate, velocity, rotation, radius, wiggle, molecular content, shock formation, periodical variation, magnetic field, etc) allows us to probe not only the jet launching and collimation, but also the disk accretion and evolution, and potentially binary formation and planetary formation in the disks. Here, the recent exciting results obtained with high-spatial and high-velocity resolution observations of molecular jets in comparison to those obtained in the optical jets in the later phase of star formation are reviewed. Future observations of molecular jets with a large sample at high spatial and velocity resolution with ALMA are expected to lead to a breakthrough in our understanding of jets from young stars.

分子喷流来自低质量恒星形成早期最年轻的原恒星。它们在 CO、SiO 和 SO 中以（亚）毫米波长检测到最内部区域，它们相关的原恒星和吸积盘深深嵌入其中，并在那里发射和准直。它们不仅是原恒星吸积历史的化石记录，而且有望在促进吸积过程中发挥重要作用。研究它们的物理特性（例如，质量损失率、速度、旋转、半径、摆动、分子含量、激波形成、周期性变化、磁场等）使我们不仅可以探测射流发射和准直，还可以探测圆盘吸积和演化，以及盘中潜在的双星形成和行星形成。在这里，回顾了最近通过分子喷流的高空间和高速分辨率观测所获得的令人兴奋的结果，并与恒星形成后期光学喷流中获得的结果进行了比较。未来利用 ALMA 对大样本、高空间和速度分辨率的分子喷流进行观测，预计将为我们对年轻恒星喷流的理解带来突破。