Abstract:A field plot experiment was conducted in order to study the effects of multifunctional conditioners on physico-chemical properties of saline soils and on straw yield of sweet sorghum in Hexi Inland of Gansu. The combination formula of the multifunctional ameliorations were A2B2C1 (nutritional factor 1.80 t/hm2, eco-organic fertilizer 72 t/hm2, saline soil amelioration 1.20 t/hm2). The results showed that the effects of different conditioners on soil bulk density, pH, EC and total salt content were in order of saline soil wasteland (CK) > Kangyanfeng saline soil amelioration > Hekang saline soil amelioration > saline soil amelioration > multifunctional amelioration; The effects of different ameliorations on total porosity, aggregates, saturated water capacity, organic matter, rapid available NPK, sweet sorghum straw yield were in order of mutifunctional ameliroation > saline soil ameliration > Hekang saline soil amelioration > Kangyanfeng saline soil amelioration > saline soil wasteland (CK). Compared to CK, Multifunctional amelioration decreased soil bulk density, pH value and total salt content by 28.05%, 3.63% and 62.16%, respectively; increased total porosity, aggregates and saturated water capacity by 45.55%, 45.55% and 32.91%, respectively; increased organic matter, alkali-hydro nitrogen, available phosphorus and available potassium contents by 11.74%, 145.01%, 206.56% and 13.35% respectively; increased sweet sorghum seedling emergence, plant height, stem diameter, fresh weight per plant and straw yield by 123.69%, 120.00%, 105.29%, 133.33% and 181.13%, respectively. Multifunctional amelioration dosage was positively correlated with saline soil porosity, aggregates, water holding capacity, organic matter, rapid available NPK, microorganism quantity, sweet sorghum straw yield, but negatively correlated with bulk density, pH value and total salt content. The regression model between multifunctional amelioration dosage (x) and sweet sorghum straw yield (y) was: y = 32.64 + 0.5561x – 0.0003x2, the optimal dosage was 75.00 t/hm2 and sweet sorghum straw yield was 72.66 t/hm2. The above results proved that the use of multifunctional amelioration can effectively improve saline soil properties by reducing bulk density, pH, EC, and total salt content, increase total porosity, aggregates, saturated water capacity, organic matter and available NPK, and increase sweet sorghum straw yield.