This paper is devoted to study the population dynamics of a single species in a one-dimensional environment which is modeled by a reaction–diffusion–advection equation with free boundary condition. We find three critical values \(c_0\) , 2 and \(\beta ^*\) for the advection coefficient \(-\beta \) with \(\beta ^*>2>c_0>0\) , which play key roles in the dynamics, and prove that a spreading-vanishing dichotomy result holds when \(-2<\beta \leqslant c_0\) ; a small spreading-vanishing dichotomy result holds when \(c_0<\beta <2\) ; a virtual spreading-transition-vanishing trichotomy result holds when \(2\leqslant \beta <\beta ^*\) ; only vanishing happens when \(\beta \geqslant \beta ^*\) ; a virtual vanishing-transition-vanishing trichotomy result holds when \(\beta \leqslant -2\) . When spreading or small spreading or virtual spreading happens for a solution, we make use of the traveling semi-wave solutions to give a estimate for the asymptotic spreading speed and asymptotic profile of the right front.