The existing combined precision seeder for rapeseed would tilt when it delivers fertilizer into seedbed simultaneously with rape seed, which is affected by the change of land slope and other factors, and it has persistent challenge that solving the problem fertilizer strip is concentrated cause uneven application of fertilizer and low fertilizer efficiency in the field, highlighting a need for investigating the unclear problem that change law of fertilizer amount in each strip under inclined state. In order to clarify the relationship between uniformity of fertilizer and inclined state, the fertilizer system combined precision seeder for rapeseed was taken as the research object, and the dynamic model of fertilizer particles under different inclined state was constructed, which was used to analyze the influence of inclined state on the flow characteristics of fertilizer. Firstly, the working condition of seeder in the field under the different tilted angle in the range of 1°~5° was simulated by test platform, and single factor experiment was carried out to investigate the influence of the different inclined states with apiece row consistency variability coefficient and the stability variability coefficient of the outer groovewheel fertilizer. Furthermore, the mathematical model of the influence of the inclined state with the fertilization uniformity was established. The test results showed that the apiece row consistency variability coefficient and the stability variability coefficient of the fertilizer feed was 8.75% and 0.89% when the seeder was in the horizontal ideal state;while with the increase of the angle range of single swing or reciprocating swing in the operation direction, the apiece row consistency variability coefficient and stability variability coefficient of the fertilizer feed were gradually decreased, with the lowest value of 8.35% and 0.41%, which indicated that the swing along the operation direction had an enhancement effect on the fertilization uniformity of the fertilizer feed. However, with the increase of the angle range of single swing or reciprocating swing in the vertical operation direction, the apiece row consistency variability coefficient and stability variability coefficient of the fertilizer feed were gradually increased, and the maximum values reached 11.41% and 2.16% when the inclination angle was 5°. This study provided a reference for field production and fertilization performance optimization of rape synchronous deep fertilization seeder.