Objective        To explore the effect of harmful factors on pulmonary functions of crews in tank cabins.       Methods        One hundred and ninety-six soldiers occupied in tanks (observation group) and 156 soldiers without any tank-related exposure in the same forces (control group) were selected in the study randomly. The pulmonary functions were tested i

n both groups. The test items included forced vital capacity (FVC)

forced expiratory volume in first second (FEV

1

)

FEV

1

to FVC ratio (FEV

1

/FVC)

maximal mid-expiratory flow (MMF)

peak expiratory flow (PEF)

and forced expired flow at 25%

50% and 75% of FVC (FEF25

FEF50 and FEF75).       Results        FEV

1

MMF and FEF50 in the observation group were significantly lower than those in the control group (P0.05

P0.01). The rates of abnormal FVC

FEV

1

FEF25 and incidence of pulmonary function damage in the observation group were significantly higher than those in the control group (P0.05

P0.01). Compared with the control group

FEV

1

MMF and FEF50 in the crews with 6 to 8 years of occupational period decreased significantly (P0.05

P0.01)

and FEV

1

in the crews with 3 to 5 years of occupational period decreased significantly (P0.01). According to different roles of the crews in a tank

FVC and FEV

1

of tank conductors

FEV

1

MMF

FEF50 and FEF75 of tank gunners

and FVC and FEV

1

of tank drivers decreased significantly (P0.05

P0.01) as compared with the control group.       Conclusion        Harmful factors in tank cabins lead to pulmonary function damage in tank crews

especially in tank conductors and gunners with 6 to 8 years of occupational period.