In this paper, we investigate the growth of solutions of the differential equations f^((k))+ A_(k-1)(z)f^((k-1))+ ··· + A_0(z)f = 0, where A_j(z)(j = 0, ···, k-1) are entire functions.When there exists some coefficient A_s(z)(s ∈ {1, ···, k-1}) being a nonzero solution of f''+P(z)f = 0, where P(z) is a polynomial with degree n(≥ 1) and A_0(z) satisfies σ(A_0) ≤1/2 or its Taylor expansion is Fabry gap, we obtain that every nonzero solution of such equations is of infinite order.
