We present some results on the existence, uniqueness and Hyers-Ulam stability to the solution of an implicit coupled system of impulsive fractional differential equations having Hadamard type fractional derivative. Using a fixed point theorem of Kransnoselskii's type, the existence and uniqueness results are obtained. Along these lines, different kinds of Hyers-Ulam stability are discussed. An example is given to illustrate the main theorems.