Abstract: ObjectiveThe present study was conducted to establish and optimize transconjugation system of Strepto-myces chartreusis WZS021(hereinafter referred to as strain WZS021),in order to enrich strain WZS021 gene fragment trans-fer technology. MethodAs donor strain,Escherichia coli ET12567 (pUZ8002) contained integrative plasmid pSET152. Strain WZS021 was recipient. Transconjugation was conducted on strain WZS021. ResultThe optimal conditions were as follows:Gauze's medium No.1 as the transconjugation medium, heat shock at 50℃for 10 min, donor-recipient ratio 1:10, 20.0 mg/L apramycin coverage 12 h post transconjugation, and adding MgCl2 till final concentration of 5.0 mmol/L. Under these conditions,the transconjugation efficiency was the highest, which was up to 3.24×10-6. ConclusionThe suitable transconjugation conditions for strain WZS021 are ascertained, and an effective genetic transformation system for strain WZS021 is established based on it. It is helpful to insert marker genes to detect nitrogen fixation sites of the strain and exogenous gene transfer.