Objectives of this study are: (1)measurement of investment efficiency indicators according to farm capacity (orchard acreage). (2) Measurement of this impact of expected technical changes (number of trees, productivity and dominant Varity structure). magor economic changes (farm capacity, price/kg of main product, cost items, return items and land rent )and their impact on investment efficiency in olive business. (3) determining the critical levels of magor changes on  investment efficiency. finishings of the study are: (1) investment efficiency is higher in olive orchards in north since ,as IRR is estimated by 30% and net present wealth is about L.E 106.4 thousands per faddan. (2) Reduction of fruitful trees to 80 per faddan instead of 120 per faddan this causes IRR to decline by 25% the switching value is estimated by 34 tree/faddan in big farm. (3)Dominant variety structure is 60% foreign and 40% local, this causes IRR to rise by 6.8%. (4) Specialization in foreign varieties is better followed pure local varieties. (5) Investment efficiency is more sensitive to high yield of foreign trees by about 10% compared with local varieties. If yield of foreign trees is increased by 10% IRR increased by 5.4% against 2.8% in local varieties the switching value of yield per tree is estimated by about 27.5% of the current productivity. (6) Efficiency response to price rise is consistent with the result obtained when tree productivity rises .The switching value of price is estimated by 31% of the current price. (7) IRR increases by about 6.8% if earning from olive increases 10% only . IF earnings from by – products increases by 10% , IRR increases by 2.8% and by 9% if earnings from main and by –products increase by 10% in the same time. (8) Impact of change in cost of manner in the highest item of cost overrun on IRR . If this item increases by 10% IRR declines by 2.8% against 8.3% if all cost overrun rise collectively by 10%. (9) The switching value of land rent reaches about L.E 11280 per faddan, assuming all other variables remain constant.