Energy is the lifeblood of modern development, and fossil energy is still the mainstream. With the growth of the world population, the rapid development of the world's industrial production and so on. Fossil energy is over-used and over-dependent, which leads to increasingly prominent environmental and energy problems. Human beings urgently need to find new, renewable and clean energy as an alternative. Microalgae, as a sustainable bio-energy raw material, has gradually entered people's field of vision. In this paper, three key problems of biodiesel production from microalgae are described :(1) the types of energy microalgae that can produce biodiesel, (2) the preparation process, and (3) the preparation of usable catalysts. The prospect of microalgae biodiesel is also prospected.