Diet is an important source of inflammation, and diet-induced inflammation might be associated with the etiopathogenesis of psoriasis. This study aimed to explore the relationship between dietary inflammatory index (DII), a literature-derived dietary tool to measure individual dietary inflammatory potential, and incident psoriasis. This was a cross-sectional study based on the 2003-2006 and 2009-2014 National Health and Nutrition Examination Surveys. The calculation of DII was based on 24-h dietary recall. Psoriasis was defined by a self-reported medical questionnaire. Logistic regressions were introduced to calculate the odds ratio (OR) and 95% confidence interval (CI) of psoriasis relative to DII. Restricted cubic splines (RCS) were used to test the nonlinear relationship in the regression model. A total of 13 284 participants with an average age of 48.94 ± 17.71 years were enrolled. The prevalence rate psoriasis was 2.88% (95% CI 2.61, 3.18). Incident psoriasis was not associated with DII in a multivariable logistic regression model (OR = 1.00, 95% CI 0.89, 1.11). Compared to participants in the lowest DII tertile, OR for those in the highest was 0.81 (95% CI 0.51, 1.28, P for trend = 0.0974). Subgroup analysis indicated that DII was still not associated with psoriasis in participants with different population settings. RCS showed that DII was not associated with psoriasis in either an overall or a nonlinear manner. Although a proinflammatory diet could lead to several health risks, psoriasis occurrence might not be associated with dietary inflammatory potential in this cross-sectional study.