Objective: To investigate the effect of high altitude span transportation on the change of hematocrit and electrocardiogram of the crew in the plateau construction, and discuss their relationship. Method: By SPSS 11.0 statistical software, to treat hematocrit and electrocardiogram in the examination data of the the crew, who took part in the construction of Qinghai-Tibetan railway in 2003, before, during and after the construction. Then, we compared the data among the constructors in the fixed altitude during the same period. Result: The hematocrit of the crew slowly and continually rose to the maximum(p<0.01) after the construction in the high altitude span during one construction year, and the abnormal rate of electrocardiogram obviously decreased(p<0.05). The abnormal rate of electrocardiogram apparently improved when hematocrit reached 52% among the range from 45.12% to 52.24%, and the correlation analysis showed that the electrocardiographic change was closely and negatively correlated with the hematocrit among the range of hematocrit(p<0.05). Conclusion: Although the higher-level stress state of the crew made the hematocrit in the blood continually increase in the long-term high altitude span construction, the hematocrit reached the more reasonable hematocrit compensation and made it the optimum state of Hct in the end. As a result, the perfusion of tissues and organs was improved. The abnormal rate of electrocardiogram apparently improved because the oxygen delivery of the myocardium reached the optimum compensation. Objective: To investigate the effect of high altitude span transportation on the change of hematocrit and electrocardiogram of the crew in the plateau construction, and discuss their relationship. Method: By SPSS 11.0 statistical software, to treat hematocrit and electrocardiogram in the examination data of the the crew, who took part in the construction of Qinghai-Tibetan railway in 2003, before, during and after the construction. Then, we compared the data among the constructors in the fixed altitude during the same period. Result: The hematocrit of the crew slowly and continually rose to the maximum (p <0.01) after the construction in the high altitude span during one construction year, and the abnormal rate of electrocardiogram obviously decreased (p <0.05). The abnormal rate of electrocardiogram apparently improved when he reached over 52 % among the range from 45.12% to 52.24%, and the correlation analysis showed that the electrocardiographic change was closely and negatively corre lated with the hematocrit among the range of hematocrit (p <0.05). Conclusion: Although the higher-level stress state of the crew made the hematocrit in the blood continually increase in the long-term high altitude span construction, the hematocrit reached the more reasonable hematocrit compensation and made it the optimum state of Hct in the end. As a result, the perfusion of tissues and organs was improved. The abnormal rate of electrocardiogram apparently improved because the oxygen delivery of the myocardium reached the optimum compensation.