Light field microscopy (LFM), featured for high three-dimensional imaging speed and low phototoxicity, has emerged as a technique of choice for instantaneous volumetric imaging. In contrast with other scanning-based three-dimensional (3D) imaging approaches, LFM enables to encode 3D spatial information in a snapshot manner, permitting high-speed 3D imaging that is only limited by the frame rate of the camera. In this review, we first introduce the fundamental theory of LFM and current corresponding advanced approaches. Then, we summarize various applications of LFM in biological imaging.Light field microscopy (LFM), featured for high three-dimensional imaging speed and low phototoxicity, has emerged as a technique of choice for instantaneous volumetric imaging. In contrast with other scanning-based three-dimensional (3D) imaging approaches, LFM enables to encode 3D spatial information in a snapshot manner, permitting high-speed 3D imaging that is only limited by the frame rate of the camera. In this review, we first introduce the fundamental theory of LFM and current corresponding advanced approaches. Then, we summarize various applications of LFM in biological imaging.