Abstract: The global energy crisis has stimulated the need to find alternative energy resources.Microalgae is a promising source of biofuel due to their simple cellular structure, higher growth rate, and higher lipid content than conventional oleaginous vegetable crops. In this article, the strains of microalgae and lipid in microalgae is introduced. Consequently, the factor of lipid accumulation in microalgae, methods of lipid extraction, genetic engineering of microalgae to increase lipid production are elucidated independently.Finally, trends and research areas in microalgae- biodiesel industry are proposed, and the integrated technology will further reduce the cost microalgal lipid production whilst making this process to be economical for the production of biodiesel.