Multi-operation within a field and multi-machinery within an operation are common in the scene of scaled farm machinery service, especially with soaring usage of automated steering system in small and medium machinery cooperatives. The object of this study is to explore a precise and efficient in-field coordination method to realize flow-shop scheduling for farm machinery fleet equipped with GNSS based auto-steering system. (1) We proposed the cloud-terminal based sketch map of coordination operation for multi-operation and multi-machinery to realize flow-shop working within a field. Supported by the Cloud, field is divided into operation strips as the smallest working workface, and farm machinery realize in-field flow-shop by using automated steering systems, which share basic A-B line and progress through the Cloud and cellular network in real time. (2) We defined three-dimensional coordinate system (XYZ), within which we defined the concept of field, operation strips, and operation tasks. Under this concept framework, we further defined operation strip state and designed its updating algorithm, which can be used for optimization simulation experiments. An operation strip is a virtual lane-shaped area of the field divided for strip-following steering during farm machinery operation with centimeter level accuracy. The operating width of strip depends on the implement width or swath of the machinery. Interval is defined to describe the operation strip in XOZ, in which the operation strips are abstracted to the line segments. The segment length is equal to the implement width or swath of machinery. Interval is described by two points corresponding to the endings of line segment. (3) To evaluate our method, we compared the waiting time between simulation experiments and a real-world case, and developed one cloud based prototype system to demonstrate the practicability. For example, plowing and seeding can be shorted from 8h to 3.8 min and from 4h to 6.3 min after disking harrow and rotary hoeing respectively. The simulations and experiments show that the in-field coordination can improve multi-machinery operation quality by reducing overlap and skip and guiding operators to operation strips, and can improve multi-operation efficiency by shortening the waiting time between each two adjacent operations. The current algorithm has a great potential to help the cooperatives to accurately compute the waiting time and effectively compact the farm machinery operation planning.