Tarom in Zanjan province, as one of the most important areas for olive culturing, with 20000 hectors and average production of more than 4.5 tons per hector, has an important role in the production of this crop. The low average yield of olive gardens can have multiple reasons that among them, pathogens is the most important agents of the performance reduction in the area. The agent of armillaria root and crown rot (Armillaria spp.), is known as the major agent of the olive trees decline in the region. Therefore because of the importance of the issue, in this research that was done in one of the Tarom olive gardens for 4 years, chemical management of the infected trees with armillaria rot was assayed in randomised complete block design. The treatments were contained the three treatments for the kind of the fungicide treatment; thiophanate-methyl (70% WP), hexaconazole (5% SC) & propiconazole (25% EC) and the two treatments for the replication of the usage per year; once usage (in April) or twice usage (in April & in July). The usage method was preparation of recommended dozen of each fungicide and waterlogging the crown of the infected trees with amount 50 liter of the solution of the fungicide. The control trees weren’t treated. All treatments carried out on the same trees. To measure the severity of the disease and the effect of fungicides, Aguín et al. (2006) method was used. All the chosen trees were fruitful and Zard variety (native and most cultivated variety of the area). The results of the treatments were assayed each year and final results were recorded after three years of treatment. Final results demonstrated that all fungicides used in this project, have sufficient efficiency to decrease the armillaria rot of the olive trees and all fungicides treatments had a significant difference at 1% level compared to control. For all fungicide treatments, twice usage of fungicide was better than once of that per each year and accordance to the results of the last year, hexaconazole (twice per year) and thiophanate-methyl (twice per year) were more better in decline symptoms decreasing and the next place belongs to hexaconazole (once per year), thiophanate-methyl (once per year), propiconazole (twice per year) and propiconazole (once per year).