Abstract： Objective To assess the precision and accuracy of bone mineral measurement utilizing spectral CT imaging with a European Spine Phantom (ESP).Methods Within the ESP named Num.145,there are three orderly vertebral bodies which were marked by L1 with Hydroxyapatite(HAP)of 50.0 mg/cm3,L2 with HAP of 100.0 mg/cm3,and L3 with HAP of 200.0 mg/cm3.The ESP was scanned by using gemstone spectral imaging (GSI) model ten times.Using GSI viewer,measurements of HAP-water concentration and HAP-fat concentration were done.The precision and accuracy of each parameter were evaluated by the results of relative standard deviation (RSD) and relative error (RE),respectively.The difference between each parameter with the real value was evaluated statistically by one-sample t test.The differences among the three vertebral bodies' same parameter were evaluated statistically by paired t test.Results The results of HAP-water concentration in L1,L2,L3 were (54.5 ±4.2),(113.3 ± 2.7) and (219.7 ± 7.7) mg/cm3,each of which was significantly higher than the real value(t values were 3.400,15.874 and 8.155,P＜0.01).And,the RSD values were 7.67％,2.34％ and 3.48％;the RE values were 5.3％,12.9％ and 9.8％.The results of HAP-fat concentration in L1,L2,L3 were (91.9±4.0),(149.5±2.5) and (254.2±7.2) mg/cm3,each of which was significantly higher than the real value(t values were 33.489,62.399 and 23.578,P＜0.01).And the RSD values were 4.31％,1.68％ and 2.86％; the RE values were 81.0％,49.1％ and 27.0％.In every vertebral body,the result of HAP-water concentration was significantly lower than the result of HAP-fat concentration (P＜0.01).Conclusions By utilizing spectral CT imaging,the precision and accuracy of bone mineral measurement were poor.Therefore,this method is not applicable for clinical measurement.