In this paper, we study the following critical fractional Schrödinger–Poisson system
trueright115.20007pt{ε2s(−Δ)su+Vfalse(xfalse)u+ϕu=Pfalse(xfalse)ffalse(ufalse)+Qfalse(xfalse)|u|2s∗−2u,indouble-struckR3,ε2t(−Δ)tϕ=u2,indouble-struckR3,where ε>0 is a small parameter, s∈(34,1),t∈false(0,1false) and 2s+2t>3, 2s∗:=63−2s is the fractional critical exponent for 3‐dimension, Vfalse(xfalse)∈C(double-struckR3) has a positive global minimum, and Pfalse(xfalse),Qfalse(xfalse)∈C(double-struckR3) are positive and have global maximums. We obtain the existence of a positive ground state solution by using variational methods, and we determine a concrete set related to the potentials V,P and Q as the concentration position of these ground state solutions as ε→0+. Moreover, we consider some properties of these ground state solutions, such as convergence and decay estimate.