White matter, which constituted the anatomical connections between brain regions, accounted for approximately 50% of the human brain. The crucial role of the intact white matter connections for normal brain function has been described by extensive lesion and anatomic studies. Although traditional structural techniques, such as diffusion tensor imaging (DTI), can successfully explore the white matter architecture, they failed to uncover neural activity and dynamics occurring in white matter. Blood oxygen level dependent functional magnetic resonance imaging (BOLD-fMRI) is a noninvasive technique to map brain activation and connectivity. Previous BOLD-fMRI studies primarily focused on spontaneous activity in gray matter rather than that in white matter, since white matter fMRI activation remained controversial. However, the evidence is accumulating for fMRI activation in white matter. This paper reviewed former researches on spontaneous activity in white matter, including physiological bases, neurovascular and neurometabolic coupling, brain activation, and brain connectivity. Despite the differences observed in vascular density between gray matter and white matter, BOLD effects in white matter were reported to be related to neural activity. Robust BOLD activations were detected in the posterior limb of internal capsule, anterior corpus callosum, etc. The power spectrum of resting-state white matter BOLD signals was associated with white matter density and fraction anisotropy (FA) rather than random distribution as noise. Besides, regarding to the functional connectivity of white matter, it was well established that white matter manifested an intrinsic functional organization as interacting networks of functional modules. Moreover, the functional networks of white matter were closely related to that of gray matter and white matter tracts. Several brain disorders, such as mild cognitive impairment, schizophrenia, Alzheimer’s and Parkinson disease, were characterized by functional connectivity abnormalities of white matter. Finally, the recommendations and suggestions for future study were included on the neurophysiological basis of white matter BOLD-fMRI signal using multimode imaging data and the common abnormalities in white matter across multiple psychiatric disorders.