12.8h，f为1.79。In order to manage farm machinery work system scientifically, the principles of ergonomics and a fatigue comprehensive evaluation method by heart rate and work time were proposed, and it was used for evaluating and analysis the tractor driver's fatigue in sowing work. The result showed that driving imported large power tractor in sowing work, the heart rate increase ratio is fairly low, and workload lies in light level, maximum acceptable work time (tmax) is between 14.2 h and 15.6 h, fatigue comprehensive assessment value f is between 1.21 and 1.48. While driving domestic Dongfanghong-1002-tractor, heart rate increase ratio is rather high, workload lies in normal level, tmax is 12.8h, and f is 1.79. In real operation, the working time of the driver is longer than maximum work time.