Abstract: In order to reduce the amount of chemical fertilizer used in blackcurrant orchard,and to determine the optimal reduction of chemical fertilizer and the proportion of bio-organic fertilizer addition,five fertilization treatments were designed,induding 100%chemical fertilizer,75%chemical fertilizer+25% bio-organic fertilizer,50% chemical fertilizer+50% bio-organic fertilizer,25% chemical fertilizer+75% bio-organic fertilizer,100% bio-organic fertilizer,and the control was no fertilization treatment.The effects of reducing fertilizer and applying bio-organic fertilizer on the growth,fruit quality and yield of black currant "Suiyan No.1" were studied.The results showed that plant height,crown width,fruit size,ear length,yield and economic benefit were significantly improved under the treatments of different proportions of chemical fertilizer combined with bio-ogical fertilizer.Fruit hardness,soluble solids,soluble sugar and VC content were increased and titrable acid content was decreased under the treatments of single organic fertilizer and chemical fertilizer combined with biological organic fertilizer.The optimal proportion was 50%chemical fertilizer+50% bio-organic fertilizer.