The effects of genotypes and culture conditions on the microspore culture in mustard （Brassica juncea） were studied to establish an optimal system of the microspore culture and chromosome doubling in mustard.34 inbred lines of 8 different varieties of mustard were used to conduct the microspore culture.The effects of heat shock times，concentrations of activated carbon，and densities of microspore on the rate of microspore embryogenesis were analyzed.The results showed that genotypes had a significant impact on the success of microspore culture in mustard，with 11 out of 34 inbred lines successfully producing embryoids.There were significant differences in rates of producing embryo among different inbred lines，among which Brassica juncea var. megarrhiza Tsen et Lee had the highest rate of producing embryo，reaching 23.85 embryos/anther.The optimal conditions for producing microspores in mustard were 32 ℃ heat shock for 1-2 days，culture medium containing 3-5 g/L activated carbon，and the density being 1.5×10⁵ to 2.0×10⁵ microspores/mL.The results of chromosome doubling experiment showed that immersing the stem tips in 1 g/L colchicine solution for 1 hour had a high efficiency of chromosome doubling and low chimerism，which could be used to double the chromosomes in mustard.The results of chromosome doubling test showed that 1 g/L colchicine solution soaked in stem tip for 1 hour had high doubling efficiency and less mixed-ploidy formation，which could be used to double the chromosomes in mustard.