Abstract.A numerical method for a class of forward-backward stochastic differential equations (FBSDEs) is proposed and analyzed. The method is designed around the four step scheme [J. Douglas, Jr., J. Ma, and P. Protter, Ann. Appl. Probab., 6 (1996), pp. 940-968] but with a Hermite-spectral method to approximate the solution to the decoupling quasi-linear PDE on the whole space. A rigorous synthetic error analysis is carried out for a fully discretized scheme, namely a first-order scheme in time and a Hermite-spectral scheme in space, of the FBSDEs. Equally important, a systematical numerical comparison is made between several schemes for the resulting decoupled forward SDE, including a stochastic version of the Adams-Bashforth scheme. It is shown that the stochastic version of the Adams-Bashforth scheme coupled with the Hermite-spectral method leads to a convergence rate of 3 2 (in time) which is better than those in previously published work for the FBSDEs. , finding an efficient numerical scheme for both BSDEs and FBSDEs has also become an independent but integral part of the theory. Tremendous efforts have been made during the past decade to circumvent the fundamental difficulties caused by the combination of the "backward" nature of the SDEs and the associated decoupling techniques for FBSDEs. In the "pure backward" (or "decoupled" forwardbackward) case, various methods have been proposed. These include the PDE method in the Markovian case (e.g., Chevance [8] (Lemor, Gobet, and Warin [23] and [24]).In the case of coupled FBSDEs, however, the results are very limited, largely due to the lack of a solution method itself in such cases. It has been well understood