Abstract: Background　The low-pressure, hypoxic environment of high-altitude areas serves as a natural physical training ground, where significant changes in physical fitness occur before and after acclimatization training. Currently, there is no standardized quantitative criterion for individual physical fitness during high-altitude acclimatization, which presents considerable limitations in providing targeted guidance for scientific training.Objective　To conduct precise classification of individual physical fitness in acclimatized youth at high altitudes based on test data, explore the correlations between different physical fitness dimensions and routine blood as well as biochemical indicators, and provide a scientific reference for optimizing guidance strategies for high - altitude physical training. Methods　A cohort of healthy male youth residing in low-altitude areas (1 300 m) was recruited. Participants underwent training at high altitude (3 000 - 3 500 m). Ten physical fitness tests (e.g., grip strength, 3 000-m run, standing long jump) and 23 blood indicators (hematology and biochemistry) were assessed pre-departure and after 6 months of acclimatization. Seven dimensions were identified via correlation analysis (|r|＞0.45, P＜0.001) and physiological rationale: upper body strength, lower-body power, cardiorespiratory endurance, strength endurance, agility, flexibility, and coordination. Individual scores per dimension were calculated using percentile-based grading (top 5%=10 points; bottom 5%=0 points). Participants were classified into types based on their dominant dimension. Superior (top 10%) and inferior (bottom 10%) groups within each dimension were compared for blood indicators. Statistical significance was set at q＜0.05 after Bonferroni correction.Results　A total of 198 healthy young males were selected, with an average age of (20.18±1.53) years. Participants were classified into seven fitness types: upper-body strength (n=23), lower-body power (n=26), cardiorespiratory endurance (n=39), strength endurance (n=39), agility (n=37), flexibility (n=47), and coordination (n=44). Significant changes in physical fitness were observed after high-altitude acclimatization: improvements in lower-body power (+5% in standing long jump, P＜0.001), upper-body strength (+3% in grip strength, P＜0.001), and coordination (-7.5% in hexagon jump time, P＜0.001) contrasted with declines in cardiorespiratory endurance (+5.4% in 3 000 m run time, P＜0.001), strength endurance (-8.3% in push-up count, P＜0.001), and agility (+16.4% in T test time, P＜0.001). Comparative analysis of blood biomarkers between superior (＞90%) and inferior (＜10%) groups within each dimension revealed dimension-specific differences, upper-body strength showed significant elevations in creatinine (CRE), lactate dehydrogenase (LDH), and α-hydroxybutyrate dehydrogenase (α-HBDH) (q＜0.05); lower-body power demonstrated increased creatine kinase (CK), α-HBDH, LDH, and neutrophil count (q＜0.05); cardiorespiratory endurance exhibited higher mean corpuscular hemoglobin concentration (MCHC) (q＜0.05); agility displayed elevated α-HBDH (q＜0.05); strength endurance presented increased CK and α-HBDH with concurrent reductions in eosinophil percentage and count (q＜0.05); coordination showed higher CK isoenzyme (CK-MB) and CRE (q＜0.05); while flexibility exhibited no significant differences.Conclusion　This study proposes a data-driven method for characterizing and evaluating physical fitness, which refines plateau physical fitness into 7 dimensions and establishes an individualized typing model incorporating differences in blood indicators. It can provide rational suggestions for scientific guidance of plateau physical fitness training and intensity allocation of operational tasks, and expand new fields in the research on quantitative evaluation of plateau physical fitness.