The main factors affect cabbage hypocotyl protoplast isolation,purification and cultivation were studied,in order to establish a practical technology system of isolation,purification,collection,culture and eventually a complete plant regeneration for cabbage protoplast.Then establish a basis for latter research such as asymmetric cell fusion and finally provide the conditions for cabbage variety improvement and innovation.The results are as follows：Protoplasts were isolated by enzyme digestion from hypocotyl of 4 day-old seedling of head cabbage.The optimum enzyme combination was attained with 2.5% cellulase R-10+0.05% pectolase Y-23+9CPW+5 mmol/L MES.In the basic medium of improved B₅ supplemented with 0.5 mg/L 2,4-D,0.2 mg/L 6-BA,0.2 mg/L NAA,the cells divided luxuriantly.Regenerated plants were formed from callus after bud induction and root initiation.In 24 regenerated plants,19 were normal diploid,4 were diploid/tetraploid chimera and 1 was tetraploid.