Through three years of positioning experiment，the effects of organic manure replacing chemical fertilizer with equal nitrogen on the stability and organic carbon and total nitrogen content of soil aggregates in potato field of semi-arid area， in order to explore the appropriate proportion and effects of organic manure replacing chemical fertilizer，and achieve the reducing fertilizer and increasing fertilizer efficiency. Five different fertilization treatments were set up in the field experiment： 100% chemical fertilizer nitrogen（CK），25% organic manure nitrogen +75% chemical fertilizer nitrogen（M25），50% organic manure nitrogen +50% chemical fertilizer nitrogen（M50），75% organic manure nitrogen +25% chemical fertilizer nitrogen（M75），and 100% organic manure nitrogen（M100）. The results showed that：compared with CK，organic manure replacing chemical fertilizer with equal nitrogen model was beneficial for reducing the proportion of soil microaggregates（＜0.25 mm），increasing the proportion of large aggregates（＞2 mm），and increasing significantly contents of R_0.25，mean weight diameters（MWD）and geometric mean diameter（GMD）of soil aggregates in the soil depth of 0-20 cm， organic carbon and total nitrogen contents of water stable aggregates，and the increase amplitude of large aggregates （＞2 mm）was the largest. The effect of M50 treatment was the best，which increased significantly organic carbon and total nitrogen contents of water stable aggregates by 7.32%-8.28% and 18.2%-20.3%，respectively，compared with CK. In conclusion，under the condition of loess soil in the semi-arid hilly region of northwest China，model of organic manure replacing chemical fertilizer with equal nitrogen could promote the transformation of soil microaggregates（＜0.25 mm）into macroaggregates，and increase the stability of soil aggregates and promote the enrichment of organic carbon（nitrogen）in aggregates，and increase soil organic carbon（nitrogen）storage，the effect of organic fertilizer nitrogen replacing 50% chemical fertilizer nitrogen mode was the most obvious.