Summary: We study how the noncommatative spacetime affects inflation. First we obtain the noncommutative power spectrum of the curvature perturbations produced during inflation in the slow-roll approximation. This is the explicit \(k\)-dependent power spectrum up to first-order in slow-roll parameters \(\varepsilon_i, \delta_1\) including the noncommutative parameter \(\mu\). In order to test the role of \(\mu\) further, we calculate the noncommutative power spectrum using the slow-roll expansion. We find corrections which arise from the change of pivot scale and the slowly varying nature of \(\mu\). It turns out that the noncommutative parameter \(\mu\) could be considered as a zero order slow-roll parameter and the noncommutative spacetime effect provides a negatively large running spectral index.