Stalk set-row planting has been one of the conservation tillage systems to minimize the frequency or intensity of tillage operations in northeast China. The agricultural management approach can integrate the tillage and planting operations to cover at least 30% of the soil surface with crop residues. A narrow row zone can be sown to clear out from the stalk-covered surface in the wide leisure zone. However, the pesticide liquid cannot reach the stalk strip surface, particularly when weeding the crop during the seedling stage under stalk mulching in the traditional full-coverage spraying mode. In this study, a precision spraying device was designed to promote the utilization rate of pesticide liquid using image recognition. Firstly, a digital camera was mounted in front of the plant protection machine to real-time capture the stalk set-row planting images in fields. A Digital Signal Processor (DSP) was used as the host computer to preprocess the images. Then, an optimized multi-threshold segmentation was performed on the images of stalk and seedling strip parts. A series of morphological operations were utilized to correct the dividing edges, where an external moment was selected to frame and separate the seedling strip areas of the field. As such, the position of the seedling strip center was evaluated to mark out the line of the seedling strip. Secondly, an STM32 microcontroller was used as the lower computer. Specifically, the controller drove the stepper motor slide to move the nozzle on the top of the seedling strip for spraying, according to the line coordinates of seedling strip positioning. At the same time, a multi-subdivision drive was used to improve the operation precision of the stepping motor. Nevertheless, some unfavorable conditions occurred in the horizontal and vertical kinds of airflow during spraying, whether the droplets drifted into the stalk rows, or the uneven spraying was caused by the air. Therefore, the drift rate of the droplet was calculated under different velocities of airflow using Fluent fluid simulation software. After that, the fuzzy controller was set up, with the horizontal and vertical airflow speed as the input, and the spray volume as the output. The spray volume was changed to adjust the opening degree of the electric valve for a better uniform settlement of the chemical liquid. Finally, the precision spraying device on a platform was tested to verify the simulation in the field. The test results showed that the accuracy of the self-developed device was about 88.3% for the positioning line of the seedling strip. A WFS-II integrated test bench was used to evaluate the spray performance. The spraying of a single nozzle was measured on the rows to save the liquid by about 64.8% more than before. The qualified rate of spraying on the rows was about 85.8% than before. The variable spraying test was conducted to maintain the liquid coverage at 28.5%-33.8% in the variable spraying mode. The field trials demonstrated that the precision spraying saved about the pesticide liquid of 52.84% in the stalk set-row planting mode, compared with the traditional full-coverage one. Furthermore, the uniformity level of liquid deposition was also improved significantly. Consequently, this device can be expected for the plant protection machinery in the precision application of seedling strips during the stalk set-row planting. The finding can provide a strong reference for the precision spraying to improve the liquid utilization rate and environment, particularly for the technical support to promote the conservation tillage.