Background and objective: Motor performance plays an important role in daily activities for older adults. The purpose of the study was to construct a method for measuring physical fitness age that can be used to assess motor performance in elderly men and to verify its validity. Methods: Four items of physical fitness including grip strength, balancing on one leg with eyes open, 30 s chair stand test and 6 min walk test were selected and measured in a random order. Principal component analysis was employed to build physical fitness age based on motor performance variables from 94 elderly men with a mean age of 71.20 \pm 5.05 years. Physical fitness age = 115.516-0.652 \times grip strength - 0.142 \times balancing on one leg with eyes open - 0.839 \times 30 s chair stand - 0.061 \times 6 min walk distance + 0.541 \times chronological age. Results: Validation test from 13 men with exercise habit and 12 men without exercise habit showed that the physical fitness age in the exercised adults was significantly lower than its chronological age (63.91 \pm 5.40 vs. 70.92 \pm 4.17, P 0.001), while no significant difference was observed between physical fitness age and chronological age in the elderly without exercise habits (71.23 \pm 7.49 vs. 70.83 \pm 5.19, P = 0.646). Conclusion: Physical fitness age is a valid indicator to evaluate and monitor motor performance. Participation in physical exercise may lower the physical fitness age by improving motor performance.