According to agricultural machinery operation in headland pattern, through installing intelligent monitoring terminal in the agricultural machinery, data of spatial track of agricultural machinery was collected, the distribution frequency of azimuth angle was analyzed, the direction of agricultural machinery operation was calculated, the agricultural machinery operation lines were extracted, and model of row spacing of agricultural machinery operation was built. Furthermore, in order to verify the algorithm of row spacing of agricultural machinery operation, field experiments were conducted on June 25, 2021 at the National Precision Agriculture Demonstration Research Base in Beijing, China. The tractor installed automatic navigation system was selected, different row spacings were set by navigation system, such as 3.0m，4.0m and 5.0m. According to the set value of row spacing, the agricultural machinery operation experiment was carried out three times in headland pattern. The results showed that the average error was 3.07% between the set value of row spacing and model calculated value. The RMSE of validation was 0.14m. Overall, conclusion analysis of an example showed that its results were coincided with the active situation. Row spacing was an important parameter of farm machinery operation supervision, combined with the width of operation, it can provide data support to quality evaluation of agricultural machinery operation, such as overlapping and omission and so on.