In general, a Lyapunov functional is one of the main approaches to show the existence of strong traveling wave solutions. However, introducing a spatiotemporal delay into a nonlocal diffusive epidemic model will bring great difficulties to the construction of a Lyapunov functional. In this paper, a new Lyapunov functional will be constructed to solve the problem of strong traveling wave solutions for a nonlocal diffusive SIR model with a spatiotemporal delay. Our results improve some known results in Wu et al. [J. Math. Phys. 61, 061512 (2020)] and Yang et al. [Appl. Anal. (in press)] by removing an a priori condition.