Abstract: Objective: To three-dimensionally, dynamically and quantitatively investigate the endoplasmic reticulum of cerebrospinal fluid leukemia cells and lymphoma cells by laser scanning confocal microscope （LSCM）. Methods: Endoplasmic reticulum of all lymphocytes （normal lymphocytes, leukemia cells, cured leukemia cells and lymphoma cells） were stained with fluorescent probe DioC 6 （3）, sectional scanograph and fluorescent intensity stereophotography were obtained and finally fluorescent values of cellular endoplasmic reticulum were individually measured. Results: Compared with normal lymphocyte cells, endoplasmic reticulum three-dimensional character of leukemia cells and lymphoma cells were varied and fluorescent value differences were statistically significant （P＜0.01）. Compared with cured leukemia cells, endoplasmic reticulum three-dimensional character of leukemia cells was varied and fluorescent value differences were statistically significant （P＜0.01） too. Conclusion: The experimental works mentioned above may be useful for central nervous system leukemia and lymphoma diagnosis, differential diagnosis, judgement of cells differentiation level and function.