A generalized Riemann hypothesis states that all zeros of the completed Hecke L-function L * (f, s) of a normalized Hecke eigenform f on the full modular group should lie on the vertical line Re(s) = k 2 . It was shown in [7] that there exists a Hecke eigenform f of weight k such that L * (f, s) = 0 for sufficiently large k and any point on the line segments Im(s) = t 0 , k−1 2 < Re(s) < k 2 − ǫ, k 2 + ǫ < Re(s) < k+1 2 , for any given real number t 0 and a positive real number ǫ. This paper concerns the non-vanishing of the product L * (f, s)L * (f, w) (s, w ∈ C) on average.