In this paper, we first give some characterizations of e-symmetric rings. We prove that R is an e-symmetric ring if and only if a1a2a3 = 0 implies that a σ(1) a σ(2) a σ(3) e = 0 , where σ is any transformation of {1, 2, 3}. With the help of the Bott-Duffin inverse, we show that for e ∈ M E l (R) , R is an e-symmetric ring if and only if for any a ∈ R and g ∈ E(R) , if a has a Bott-Duffin (e, g)-inverse, then g = eg. Using the solution of the equation axe = c , we show that for e ∈ M E l (R) , R is an e-symmetric ring if and only if for any a, c ∈ R , if the equation axe = c has a solution, then c = ec. Next, we study the properties of e-symmetric *-rings. Finally we discuss when the upper triangular matrix ring T2(R) (resp. T3(R, I)) becomes an e-symmetric ring, where e ∈ E(T2(R)) (resp. e ∈ E(T3(R, I))).